New Hg2+-Selective Fluorescent Sensor based on...

Pure and Applied Chemistry International Conference 2014 ANC-1

Analytical Chemistry ANC-OR-01

New Hg2+

-Selective Fluorescent Sensor based on

Naphthalimide System

Yordkhuan Tachapermpon1, Narupon Prapawattanapol

2, Kullatat Suwatpipat

1,Nantanit Wanichacheva

1,*

1Department of Chemistry, Faculty of Science, Silpakorn University, NakhonPathom 73000, Thailand 2Department of Petrochemistry and Polymer Science, Faculty of Science, Chulalongkorn University,

Bangkok 10330, Thailand

*E-mail: [email protected]; [email protected]

Two novel fluorometric sensors based on 2-(3-(2-aminoethylsulfanyl)propylsulfanyl)ethanamine

covalently bound to one and two modified naphthalimide moieties (1 and 2) were designed and

synthesized for the optical detection of Hg2+

ions. The sensors were prepared by N-alkylation,

imidation and nucleophilic aromatic substitution in three-step synthesis using inexpensive starting

materials. The compounds were characterized by 1H NMR,

13C NMR and Mass spectrometry.The

sensitive and selective binding behaviors of sensors were investigated by fluorescence

spectroscopy. Especially, sensor 1 provided highly Hg2+

-selective ON-OFF fluorescence

quenching behaviors and discriminated various interfering ions such as Cu2+

, Ag+, Cd

2+, Mn

2+, K

+,

Pb2+

, Na+, Fe

2+ and Co

2+ with the detection limit of 22 ppb.

Keywords Mercury sensor; Naphthalimide; Fluorescent sensor

mailto:[email protected]




Fluorescence Sensor Inside Surfactant Sphere for Selective

Detection of p-Phenylenediamine

Kessarin Ngamdee1, Surangkhana Martwiset

1, Thawatchai Tuntulani

4, Wittaya Ngeontae

1, 2, 3,*

1Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in

Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen, 40002, Thailand 2Research Center for Environmental and Hazardous Substance Management, Khon Kaen University,

Khon Kaen 40002, Thailand 3Center of Excellence for Environmental and Hazardous Waste Management (EHWM),

Bangkok 10330, Thailand 4Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

*E-mail: [email protected]

A selective fluorescence sensor for the determination of p-phenylenediamine (PPD) was fabricated

from the alizarin-boronic acid adduct with an assistance of surfactant. Basically, Alizarin Red S

(ARS) is not a fluorescence active compound. However, fluorescence intensity can be observed

when ARS reacted with 4-formylphenylboronic acid (4-FPBA) and provided the boronate ester

adduct (ARS/4-FPBA). Upon the addition of PPD, the fluorescence intensity of the ARS/4-FPBA

adduct decreased as a linear function of PPD concentrations. Sensitivity and selectivity of this

fluorescence sensor were improved by incorporating the sensor molecule into the hydrophobic core

of micelles. Various parameters that could possibly affect the fluorescence quenching of boronate

ester adducts by PPD were investigated and optimized. Under the optimized condition, the working

linear concentration range was found to be 0.03-0.40 mM and the calibration sensitivity was 48

times higher than that from the system containing only buffer solution.

Keywords p-Phenylenediamine; Micelle; Fluorescence sensors; Chemical sensors



Sensor Devices for Health Applications based on Smart

Miniaturised Microsystem Technology

Eric Moore*, Walter Messina, Una Crowley, Gerard Duffy, Lisa Helen, Niall Savage, Shauna Scanlon and

Michelle Fitzgerald

Life Science Interface, Tyndall National Institute, University College Cork, Lee Maltings,

Prospect Row, Cork,Ireland.

*E-mail:[email protected]

The component and systems business in Europe concentrates on added value operations, on system

integration, on novel technologies and on enabling the end-user industry to offer new technologies

and total product/service solutions. Increased multi-disciplinary, integrated software/hardware

systems, heterogeneous microsystems and the use of widely distributed systems for monitoring

control are growing challenges. Microsystems exist to integrate and interface multiple core

technologies and related materials to implement a variety of functions. They are implemented

through scalable homogeneous or heterogeneous hardware integration technologies in order to

advance miniaturisation, functionality and reliability of the sensing, processing, actuating and

communication functions.This paper presents a range of sensing (electrochemical, impedance,

immunosensor etc.) and separation devices (capillary electrophoresis) that are being developed at

Tyndall National Institute which, are module in nature and can be integrated into lab-on-chip

systems. We are using tools and processes of nano/micro-technology to address challenges in

biology with the objective to develop miniaturised devices and systems that are simple, label-free,

and sensitive, and developed according to end user requirements.Theseintegratedsystemswill

address markets including health, pharmaceutical industry, environmental monitoring, food,

beverage and security/defence sectors.



Development of an Optical Chemical Sensor for Cu(II) based on

5-Methyl-4-(2-thiazolylazo)resorcinol Immobilized on Amino-

silica/Chitosan Film

Kotchakriangkrai Sanai, Jatuporn Wittayakun, Sanchai Prayoonpokarach*

Material Chemistry Research Group, School of Chemistry, Institute of Science, Suranaree University of

Technology, Nakhon Ratchasima 30000, Thailand


A chomogenic sensing reagent, 5-methyl-4-(2-thiazolylazo)resorcinol, was immobilized onto a

film composed of 5 %wt of amino-silica particles and chitosan and the film was used for the

determination of Cu(II) in water samples. Parameters that affect the response of the sensing film to

Cu(II) were investigated. In the presence of Cu(II), the sensing film had the absorption maximum

at 555 nm and the optimum response was achieved in a solution of pH 4.5. A linear calibration

curve was obtained with Cu(II) concentration in the range of 0.10 to 40 ppm with a response time

of 10 min and the linear equation was log(absorbance) = -0.5691logCcu+2.667 with r2 = 0.9959.

The limit of detection was 20 ppb calculated based on three times standard deviation of the blank

signal. No significant interferences were observed. The sensing film exhibited good stability with

the operational lifetime of 3 weeks. Regeneration of the sensing film after the exposure to Cu(II)

was succeeded by soaking the film in 1 M HCl for 2 min.

Keywords Optical chemical sensor; Chitosan film; Amino-silica particles; Copper(II)

http://www.sciencedirect.com/science/article/pii/S0925400512003346





Novel Miniaturized Flow Analysis Systems

for Determination of Aluminium(III)

Paweelada Prasertboonyaia, Orn-anong Arquero

a, Teraboon Pojanakaroon

a and Saisunee Liawraungrath

a,b*

aDepartment of Chemistry, Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand bInstitute for Science and Technology, Chiang Mai University, Chiang Mai 50200, Thailand

*E-mail: [email protected] (S.Liawruangrath)

A simple and low-cost polymethyl methacrylate (PMMA) chip is designed and fabricated by laser

ablation and thermal bonding. The micro-flow analysis (µFA) manifold was consisting of the

polymethyl methacrylate (PMMA) chip with µ-channels as flow lines was employed as micro

reactor. The µFA system was coupled with a light emitting diode (LED) as light source. As soon as

the sample was reached the µ-reactor the emitting light was absorbed by which was passed the

sample species into the flow cell of the spectrometer where the absorbance was measured. It is

based on the reaction of aluminium(III), with bromopyrogallol red in the presence of

cetyltrimethylammonium bromide (CTAB) to solubilize the complex yielding a violet colored

complex in an acetate buffer medium (pH 5.0). Measurements were made at the λmax of 600 nm.

Optimum conditions for determining aluminium(III) using the proposed micro reverse flow

injection (µrFI) manifold was investigated. A linear calibration curve was obtained over the range

of 0.05–0.80 mg L−1

with a correlation coefficient of 0.9995. The proposed method was applied to

the determination of aluminium(III) in carbonated beverages samples. Results obtained were in

good agreement with those obtained by the official ICP-OES method at the 95% confidence level.

Keywords Aluminium(III), Bromopyrogallol red, Micro reverse flow injection (µrFI)



Modification of Water Bath as a Newly Digestion Apparatus

and Application for Preparation of Mushroom Sample Prior to

Determine Fe Concentration by AAS

Witphon Thosaikham, Rossukon Sittipout, Piyanete Chantiratikul*

Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC),

Faculty of Science, Mahasarakham University, Kantarawichai,

Maha Sarakham, 44150, Thailand


A water bath was modified as a newly digestion apparatus by designing and constructing as a

closed-vessel digestion system that consisted of 4 main devices; water bath, cover plate, vessels

and wind tunnel. The conditions of the proposed digestion apparatus; volume of nitric acid,

digestion temperature and digestion time were optimized for decomposing 0.1 g of Phellinnus

linteus as a homogeneous solution before determination of Fe by AAS. The optimum value of each

condition was 2.0 ml, 100 °C and 30 min, respectively. Repeatability and reproducibility of the

proposed digestion method in term of relative standard deviation (RSD) were less than 10%. The

percentage recovery of Fe was 95%. The digestion efficiency of the proposed digestion method

was as well as the recognized digestion methods; microwave-assisted digestion, opened-wet acid

digestion and better than dry ashing methods. Furthermore, applications of the proposed digestion

method for digesting other medicinal and edible mushrooms were also achieved to determine Fe

concentration. Hence, the water bath has been successfully constructed as a high efficiency,

economics digestion apparatus that could be alternation for preparing sample materials.

Keywords Water bath; Mushroom; Closed-vessel digestion




Novel Microfluidic System for Simultaneous Analysis of Some

Chemical Parameters in Natural Waters

Napaporn Youngvises1*, Jakrawut Panityotai

2, Prawit Rungrairatanaroij

2,

Waraporn Threeprom3, Jaroon Jakmunee

4

1Department of Chemistry and Research Unit of Innovative Green Chemistry, Faculty of Science and

Technology, Thammasat University, Pathum Thani, 12120, Thailand 2Department of Physics, Faculty of Science and Technology, Thammasat University,

Pathum Thani, 12120, Thailand 3Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Mahidol University, Rajathewi, Bangkok, 10400, Thailand 4Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Chiang Mai University, Chiang Mai, 50200, Thailand


Our research focuses on “Green Analytical Chemistry” especially to minimize the reagent

consumption and waste generation using lab on a chip analysis. Novel lab on chips have

been designed and invented in our laboratory with the purpose to apply in multi-analysis

incorporating to bench made optical sensor. The channel networks were fabricated on both sides of

PMMA by CO2 laser (with 250 µm wide) for simultaneous analysis some chemical parameters

such as nitrite, nitrate, phosphate, ferrous, ferric and cupric ions in natural waters using specific

reagents to produce the color in each flow cells in the chip. The novel chip was designed in

hexagonal shape and fixed both sides by two pieces of PDMS. The signals were monitored and the

linearity of these analyses were studied in the range of 0.1-50 mg L-1

and R2 were higher than 0.99.

The percentage relative standard deviations for 10-replicate injections for each analyte were less

than 4. Keywords Lab on a chip, Microfluidic analysis, Natural waters, Chemical parameters



Quantitative Flow Analysis of Ammonium in Water Samples

with On-line Membraneless Vaporization of Ammonia Gas

Coupled with a Contactless Conductivity Based-Detection

Waleed Al-Ahmad,1,2

Thitirat Mantim,1,2

Nuanlaor Ratanawimarnwong,1,3

Duangjai Nacapricha,1,2

*

1Flow Innovation-Research for Science and Technology Laboratories (FIRST labs) 2Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Mahidol University, Bangkok10400, Thailand 3Department of Chemistry, Faculty of Science, Srinakharinwirot University,



The recent design of a separation device, known as „membraneless vaporization (MBL-VP) unit‟

[1], was used to develop a flow system for direct determination of ammonium in a complex sample

such as wastewater. The MBL-VP unit was used as on-line device to separate ammonia gas from

the sample fluid. After mixing with an alkaline medium to convert ammonium to ammonia, 300

µL of the sample fluid was transported into the donor reservoir of the MBL-VP unit. Ammonia

gas diffused across the headspace and dissolved into a fluidic zone of 10 µM hydrochloric acid (150

µL) rested in the acceptor reservoir in the MBL-VP unit. Dissolution of ammonia resulted in

decrease in the conductivity of the hydrochloric acid acceptor. The change in conductivity was

detected by using a homemade „capacitively coupled contactless conductivity detection‟. Linear

calibration (20-100 µM) was obtained using 3-min diffusion time (y = (0.010 ± 0.0002)x (- 0.162 ±

0.011): r2 = 0.998), with LOD and LOQ found at 10 and 34 µM, respectively. If the diffusion time

was increased to 6 min, the calibration could be extended to low concentration down to 5 µM. At

6-min diffusion, the linear calibration was also obtained (5-100 µM) (y = (0.009 ± 0.0002) x + (- 0.003 ± 0.010): r

2 = 0.996), with LOD and LOQ found at 4 and 14 µM, respectively. The precisions for both

concentration ranges were acceptably good (RSD <2.5%). The flow system was applied to

determine ammonia in wastewater without needs of pre-treatment of sample apart from basic

filtration.

Keywords Membraneless vaporization, Capacitively coupled contactless conductivity detection,

Ammonium, Wastewater.



Determination of Unconjugated Estriol by using Surface

Plasmon Resonance (SPR) Biosensor

Kitti Boonperm1, Nongluck Houngkamhang

1, Thidarat Wangkam

3, Apirom Wongsakulyanon

4,

Verayuth Praphanphoj5, Boonsong Sutapun

6, Toemsak Srikhirin

1,2*

1. Materials Science and Engineering Program, Faculty of Science, Mahidol University,

Bangkok, 10400, Thailand 2. Department of Physics, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand

3. Department of Industrial Physics and Medical Instrumentation, Faculty of Applied Science, King

Mongkut's University of Technology North Bangkok, Bangkok, 10800, Thailand 4. Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol Unversity,

Bangkok, 10400, Thailand 5. Center for Medical Genetics Research, Rajanukul Institute, Bangkok, 10400, Thailand

6. School of Electronic Engineering and School of Telecommunications Engineering, Suranaree University of

Technology, Nakhon Ratchasima, 30000, Thailand.


Unconjugated estriol (uE3) is one of the estrogen hormone produced in significant amount during

the pregnancy. It can be measured in maternal blood and its level can be used as a marker for

screening the down syndrome. An abnormally low level of uE3 indicates a chance of baby

suffering from a down syndrome, lower than 0.68 ng/mL in the second trimester. The main

objective of this work is to develop the technique for maternal serum screening for uE3 by using

surface plasmon resonance (SPR) technique. uE3 is a small molecule and it is very difficult to

detect directly by SPR; therefore, the inhibition assay was chosen for the study. The inhibition

assay was done by mixing uE3 sample with known amount of the antibodies. The free antibodies

bind with the uE3 in the premixed sample causing the reduction of the free antibodies. Therefore

the higher the uE3 presented in the sample, the lower the free antibodies in the mixed sample. The

amount of the uE3 was quantified against the standard curve. A limit of detection (LOD) of 0.3

ng/mL and the possibility of regenerating the sensor chip up to 6 cycles were achieved.

Keywords Unconjugated Estriol; Down syndrome; Surface Plasmon Resonance



Immobilization-free Electrochemical DNA Sensors Based On

Peptide Nucleic Acid Probes

Jutatip Kongpeth,1 Sakda Jampasa,

2 Orawon Chailapakul,

3 Tirayut Vilaivan

1*

1Organic Synthesis Research Unit, Department of Chemistry, Faculty of Science,

Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand 2Program in Petrochemical and Polymerscience, Faculty of Science

Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand

3Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry,

Faculty of Science, Chulalongkorn University, Phayathai Road, Patumwan, Bangkok 10330, Thailand


Electrochemical DNA sensors offer a rapid, sensitive and inexpensive method for DNA sequence

detection. Most of the reported electrochemical DNA sensors reported to date relies on the detection

of electrochemical signal change of an immobilized probe upon hybridization with the DNA target.

The probe is often a single stranded DNA or other nucleic acid analogues that can bind specifically

with the target. To enable electrochemical detection, an electrochemically active species must be

included as a label in the probe or as a redox indicator that can interact specifically with the probe-

target hybrid. In this work, electrochemically active pyrrolidinyl peptide nucleic acid (acpcPNA)

has been developed as a probe for immobilization-free electrochemical detection of DNA

sequences. Carboxyl-functionalized anthraquinone (AQ) and methylene blue (MB) have been used

as the redox-active label and introduced onto acpcPNA via acylation reaction at the N-terminus of

acpcPNA. Specificity of the acpcPNA-DNA interaction was studied by melting temperature

measurement. Both AQ-PNA and MB-PNA gave higher thermal stability than duplex DNA because

of the π-π interaction between the AQ or MB unit with the DNA base pairs. The electrochemical

DNA detection was studied on screen-printed carbon electrode (SPCE) using a square-wave

voltammetric (SWV) technique. The labeled acpcPNA probe in the single stranded form gave a

redox signal due to electrostatic adsorption of the labeled acpcPNA and the electrode. Hybridization

with a fully-match DNA resulted in a signal decrease due to the electrostatic repulsion between the

phosphate backbone of DNA and the negatively charged electrode surface. Accordingly, an

immobilization-free electrochemical platform for sequence-specific DNA detection was

successfully developed, with a detection limit in the low micromolar range. Keywords Peptide nucleic acid; Anthraquinone; Screen-printed electrode; Electrochemical DNA

detection


Analytical Chemistry ANC-P-001

Dual-Stage Flow Injection/Sequential Injection Hybrid System

for Continuous Liquid-Liquid Extraction

Sarawut Somnam1*, Jaroon Jakmunee

2 and Kate Grudpan

2

1Chemistry Program, Faculty of Science and Technology, Chiang Mai Rajabhat University, Chiang Mai,

50300, Thailand 2Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand


A simple and cost effective analytical system combining flow injection (FI) continuous liquid-liquid

extraction and sequential injection (SI) colorimetric detection was exploited. The standard or

sample was injected into a reagent stream to form a less polar ion-association compound in the

aqueous phase before merging with organic solvent to produce tiny segments of aqueous and

organic phases alternately. The extraction occurred at the interface of the two phases while they

were flowing through an extraction coil (EC) to be collected in a test tube. Phase separation

occurred in the test tube, then the organic phase was aspirated by a SI system to monitor the

absorbance signal with a simple LED-LDR colorimeter. The extraction and detection processes

could be operated independently. That means that while the detection of the signal was in operation,

a new sample could be immediately injected for the new cycle of extraction to minimize the use of

chemicals and time consumption. The system has been demonstrated for the determination of

anionic surfactant (AS) in wastewater samples and diphenhydramine hydrochloride (DPH) in

pharmaceutical samples. Experimental parameters that affected the extraction, i.e., cationic dye

concentration, volume ratio of aqueous to organic phase, as well as the length of EC were

optimized. The limit of detections (LOD) were found to be 0.20 mg L-1

and 1.0 mg L-1

for AS and

DPH, respectively. Sampling frequency of 25 sample h-1

was obtained. The total consumption

volume (for one sample) of aqueous phase and organic phase was 1.7 and 1.0 mL, respectively. For

application to real sample analyses (AS in wastewater and DPH in pharmaceutical), the results were

compared with those obtained by standard methods (methylene blue method for AS and HPLC for

DPH). Evaluation by t-test at 95% confidence level indicated that there was no significant

difference in the results obtained by both methods.

Keywords Flow injection; Sequential injection; Continuous liquid-liquid extraction; Anionic

surfactant; Diphenhydramine hydrochloride



Exploiting Solid Sorbed Indicators for Acidity Assay of Palm Oil

Miki Kanna1*, Sarawut Somnam

1 and Kate Grudpan

2

1Chemistry Program, Faculty of Science and Technology, Chiang Mai Rajabhat University, Chiang Mai

50300, Thailand. 2Department of Chemistry, Faculty of Science, and Center of Excellence for Innovation in Analytical Science

and Technology, Chiang Mai University, Chiang Mai, 50200, Thailand


Investigation was made to explore the possibility in applying a solid sorbed indicator for the assay

of palm oil samples. In the standard test method for determination of free fatty acids (ASTM

D5555-95(Reapproved 2001)): to a palm oil samples(28.2 g), adding ethanol ( 25 mL) with a few

drop of phenolphthalein solution (in ethanol) ; titrating this with standard (0.1000 M NaOH), with

vigorous stirring and using visual detection for end point. We studied solid sorbed indicators by

using Dowex11, Dowex1×8, and Kaolin as solid supports for indicators of phenolphthalein(PN),

thymol blue (TB), congo red (CR), crystal violet (CV) and Butterfly pea water extract (BP)

providing Dowex11_PN Dowex1×8_PN Dowex11_TB Dowex1×8_TB Dowex11_BP

Dowex1×8_BP Kaolin_BP Kaolin_CR Kaolin_CV. Instead of using plenty of organic solvent

(ethanol) in the conventional titration, employing a solid sorbed indicator was attempted for

procedures without the organic solvent,i.e direct titration with a standard aqueous sodium hydroxide

solution employing visual detection for color change of solid sorbed indicator for end point.

Dowex1×8_BP was found to be appropriate for some samples, as the results obtianed by the

developed methods agreeing with that of the standard method and with 4.5% RSD.

Keywords Solid sorbed indicator; Acid-base titration; Acidity assay; Palm oil



Phthalates Determination by using Monolithic Adsorbent

P. Khawmodjod1, O. Chienthavorn

1

1Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Kasetsart University, Chatuchak, Bangkok 10900, Thailand

Phthalates (PAEs) are plasticizers used to improve properties of plastic products. Since phthalates

are not chemically bound to polymer, they are easily leaked into the environment from plastic

wastes and anticipated to be carcinogenic. In this study, a determination of phthalates, namely di-

butyl phthalate (DBP), benzyl butyl phthalate (BBP), di-(2-ethylhexyl)-phthalate (DEHP) and di-n-

octyl phthalate (DnOP) in environmental samples was developed by using monolithic materials as

an adsorbent for sample extraction and analyzed by gas chromatography-mass spectrometry (GC-

MS). The monoliths are prepared directly inside the capillary tubing via sol-gel method and the

morphology is characterized by using scanning electron microscopy (SEM). The method was

proved to be very efficient, gaining benefits in reducing extraction and analysis time and being

environmental friendly technique.

Keywords: monoliths; phthalates; adsorbent



The Chemical Compositions and Anti- acne Inducing Bacteria

Property of Essential Oil from Clausena Lansium Leaves

Sopit Phetsang1, Nopakarn Chandet

1, Angkhana Inta

2 and Pitchaya Mungkornasawakul

1,3*

1Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand 2 Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand

3Environmental Science, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand


Essential oil is complex mixture of organic compounds, representing the plant secondary

metabolites. In this study, the essential oil from the leaves of Clausena lansium was collected from

Nan province, Thailand. This oil was extracted by steam distillation method and analyzed by gas

chromatography-mass spectrometry (GC-MS). (Z)-α-santalol, (E)-caryophyllene, (trans)-

sesquisabinene hydrate, (E,E)-α-farnesene and (E)-β-farnesene were the dominant compounds of

the oil. Moreover, the inhibitory activities against the growth of Staphylococcus epidermidis as

acne inducing bacteria of the essential oil have been shown by disc diffusion method.

Keywords Clausena lansium; Essential oils; Gas chromatography-mass spectrometry



Determination of Chromium(VI) in Cement by using a New

Extraction Procedure and Differential Pulse Cathodic Stripping

Voltammetric Method

Jaroon Junsomboon , 1,

* Pradab Sawangsri,1 Jaroon Jakmunee

2

1Physics and Engineering 2 Sub-division, Physics and Engineering Program, Department of Science Service,

Ministry of Science and Technology, Bangkok 10400, Thailand 2Department of Chemistry, and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Chiang Mai University, Chiang Mai 50200, Thailand

*e-mail: [email protected]

A new extraction procedure based on an off-line extraction column was proposed for extracting of

chromium (VI) from cements. The column was fabricated from a plastic syringe fitted at the bottom

with a cotton wool and a piece of filter paper to support a cement sample. An aliquot (150 mL) of

extracting solution (HNO3 1 mmol/L, pH 3) was used to extract the sample under gravity flow

and the eluate was collected in a polyethylene bottle. The extracted solution and ammonium

tartrate electrolyte solution were placed in a voltammetric cell, then the solution was stirred

at 2000 rpm and purged with nitrogen gas for 3 min before deposition of the metals was

carried out by applying a constant potential of 0 V versus Ag/AgCl to the hanging mercury

drop electrode (HMDE) for 45 s. Differential pulse potential waveform was scanned from 0

to -0.32 V and a voltammogram was recorded. Peak current of chromium(VI) was

measured at peak potential of -0.16 V. Standard addition procedure was used for

quantification. Relative standard deviation for 11 replicate determination of 100 µgL-1

of

chromium(VI) was 1.5%. Percentage recoveries obtained by spiking 40 µgL−1

of

chromium(VI) to the sample solution was found to be 98% and a detection limit of 2 µgL-1

was achieved. The developed method was applied to the analysis of cement samples. The

results obtained by the column extraction procedure were well correlated with those obtained by the

steady state extraction procedure, but showed slightly higher extraction efficiency.

Keywords: Differential pulse voltammetry, chromium(VI), cement



Fatty Acid Composition of Tea seed (Camellia oleifera) oil

planted in the Northern of Thailand

Aknarin Pintatum1,2

, Siripat Suteerapataranon1, Kanchana Watla-iad

1*

1School of Science, Mae Fah Luang University, Chiang Rai 57100, Thailand 2Tea Oil and Plant Oil Development Center, Chiang Rai 57130, Thailand

*E-mail: [email protected] Camellia oleifera Abel. originates from China. Its oil is well-known as the tea seed oil or

camellia tea oil which is important for the economy of the Southern China. It is usually used

for cooking and medicinal applications. The Camellia oleifera is planted in the Northern of

Thailand since 2005. Fatty acid composition of 10 samples of the tea seed oil obtained from

the Northern of Thailand were investigated. The tea seed oil samples were produced by a

single screw press. Esterification of free fatty acids were performed with boron trifluoride-

methanol conditions before analysis by a Gas Chromatography (GC). It was found that, six

free fatty acids were found in the tea seed oil. The oil samples present oleic acid (ω-9) as the

main free fatty acid between 75.23-79.73%. Furthermore, the oil also present linoleic acid (ω-

6) and linolenic acid (ω-3) too. Fatty acid composition of the oil samples planted in the

Northern Thailand show high unsaturated fatty acid between 84.47-87.73% which is similar to

that of the China tea seed oil report. The tea seed oil can apply to prevent hearth, reducing

cholesterol and decreasing blood pressure.

Keywords Camellia oleifera; Tea seed oil; Fatty acid composition; Gas Chromatography



Synthesis and Characterization of Functionalized Graphene

Oxide with 3-Mercaptopropyl-Trimethoxysilane

Prawit Nuengmatcha, Ratana Mahachai and Saksit Chanthai*

Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Khon Kaen University, Khon Kaen 40002, Thailand


The mercapto group (thiol, -SH) is one of the most important functional group of ligands,

particularly 3-mercaptopropyl-trimethoxysilane (MPTMS), which has relatively high affinity to

bind heavy metal ions. The present study was aimed to synthesize and characterize graphene oxide

(GO) modified with the MPTMS via silanization step. The effect of an initial concentration of the

MPTMS (0.8-14.4% w/v) was experimentally optimized. Then, the obtained GO-MPTMS product was

characterized by Fourier Transform infrared spectroscopy (FTIR) and energy dispersive X-ray

spectroscopy (EDX) techniques. From the results, the optimum conditions for the GO-MPTMS

production were 4.8% w/v MPTMS at 65C for 6 h. It exhibits the IR characteristic peaks at wave

numbers (cm-1

) of 3367 (O-H), 2576 (S-H), 1719 (C=O), 1224 and 1049 (C-O), and 1160 (Si-O-C)

indicating their functionalized GO-MPTMS. While EDX of this material reveals both Si and S

spectra, also indicating the MPTMS bound on the surface of GO. It could, therefore, be implied that

the GO-MPTMS was successfully obtained for further applications.

Keywords: Graphene oxide; 3-Mercaptopropyl-trimethoxysilane, Synthesis, Characterization



Preparation and Characterization of a New Nanocomposite

Sensor of ZrO2-Graphene-Cobalt Oxide on Fluorine doped Tin

Oxide Electrode

Apinya Puangjan*, Suwan Chaiyasit

Department of Chemistry, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand


A highly sensitive electrochemical sensor made of ZrO2-graphene-cobalt oxide nanocomposite on

fluorine doped tin oxide (FTO) electrode was prepared and characterized. The preparation of the

nanocomposite was done by mixing ZrO2 nanoparticles, reduced graphene oxide, and cobalt

chloride together in a certain way and then refluxing the mixture. The suspension was then dropped

onto the surface of an FTO electrode, finishing the preparation process. UV-vis adsorption

spectroscopy was performed on the nanocomposite to identify the approximate range of the

nanoparticle size. The morphology of the nanocomposite was investigated by studying the pictures

from field emission scanning electron microscopy (FSEM) and transmission electron

microscopy (TEM) of the composite. The nanocomposite identity was confirmed by X-ray

diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). This sensor has been used

successfully to detect many types of drugs such as aspirin and caffeine.

Keywords Graphene; Graphene oxide; Nanocomposites; Zirconia; FTO electrode



Optimization of Carboxylated Multiwalled Carbon

Nanotubes/polydimethylsiloxane 96-blade Solid-Phase

Microextraction System for Phenolic Compounds Analysis

Pamornrat Kueseng1, 2

, Janusz Pawliszyn2*

1School of Science, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand

2Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1,

Canada


Carboxylated multiwalled carbon nanotubes/polydimethylsiloxane (MWCNTs-COOH/PDMS)

coating was prepared through thin-film geometry. The developed coating was applied for 96-blade

solid-phase microextraction system followed by high performance liquid chromatography with

ultraviolet detection for analysis of trace phenolic compounds i.e., 2-nitrophenol, 2,4-

dichlorophenol and 2,4,6-trichlorophenol in water. Optimization of 96-blade solid-phase

microextraction parameters i.e., salt concentration, sample pH, desorption solvent, extraction and

desorption time were investigated. The MWCNTs-COOH/PDMS 96-blade SPME provided several

advantages over traditional methods due to its simplicity of use, relative low cost, high sample

throughput for up to 96 samples in 200 min, easy automation, and need of a small amount of

sample.

Keywords Solid-phase microextraction; Thin-film; Carboxylated multiwalled carbon nanotubes;

Polydimethylsiloxane; Phenolic compounds



Hydrogen Peroxide Biosensor Based on Horseradish Peroxidase

Immobilized on Poly(aniline-co-o-aminobenzoic acid) Modified

Glassy Carbon Electrode Covered with Chitosan Film

Sanoe Chairam*, Peerawich Buddhalee, Maliwan Amatatongchai

Department of Chemistry and Centre of Excellence for Innovation in Chemistry, Faculty of Science,

Ubon Ratchathani University, Warin Chamrap, Ubon Ratchathani 34190, Thailand.


A novel amperometric biosensor for hydrogen peroxide (H2O2) determination was successfully

prepared by immobilizing horseradish peroxidase (HRP) on poly(aniline-co-o-aminobenzoic acid)

or p(Ani-co-o-Aba) and then covered with chitosan (CS) film. The immobilized HRP displayed an

excellent electrocatalytic activity to the reduction of hydrogen peroxide. The effects of

experimental variables such as the o-Aba mol ratios in p(Ani-co-o-Aba) synthesis, HRP and CS

concentrations, pHs of supporting electrolyte solution and applied potentials for the working

electrode were investigated for the optimized conditions. This novel biosensor exhibits a fast

response toward H2O2 with a linear range from 10 to 1,000 M and a detection limit of 1.8 M

based on the signal-to-noise ratio (S/N = 3). The developed biosensor shows satisfactory tolerance

with other potential interferences such as dopamine (DA), ascorbic acid (AA), glucose (Glu) and

uric acid (UA), and also shows a good stability for 2 weeks.

Keywords Hydrogen peroxide biosensor; Horseradish peroxidase; Poly(aniline-co-o-aminobenzoic

acid); Glassy carbon electrode; Chitosan



Silver Nanoparticle-Based Colorimetric Assay for Selective

Determination of Nickel

Thanyaporn Kiatkumjorn1,3

, Weena Siangproh2, Narong Praphiraksit

1 and Orawon Chailapakul

1,3*

1Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science,

Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand 2Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana, Bangkok

10110, Thailand 3Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Patumwan,



A colorimetric assay based on silver nanoparticles (AgNPs) for detecting nickel ions (Ni2+

) has been

developed. Recently, AgNPs have been used for colorimetric sensor due to higher extinction

coefficients than gold nanoparticles (AuNPs). The high extinction coefficient of AgNPs leads to

improve visibility because of the difference in optical brightness and high sensitivity when using

absorption spectrophotometry. In this study, aminothiol compounds have been used to modify the

AgNPs surface which exhibits highly selectivity towards Ni2+

over other cations under specific

conditions. The infrared spectra suggested that aminothiol compounds were successfully capped on

the surface of the AgNPs. Upon addition of Ni2+

to the modified AgNPs solution, color can be

obviously observed by naked eyes due to the aggregation of AgNPs induced by the binding between

the Ni2+

and aminothiol ligands. Characterization of modified AgNPs and AgNPs aggregation were

studied by transmission electron microscope (TEM) and UV-visible spectroscopy, respectively.

Using optimal conditions, a quantitative linear range was found to be 10-150 ppb with the detection

limit of 6 ppb (S/N=3). This sensor has been used for the determination of Ni2+

with industrial

wastewater samples. Overall, this alternative approach presents simple, rapid, sensitivity and

selective detection of Ni2+

. All details will be presented and discussed.

Keywords silver nanoparticles; nickel; aminothiol; colorimetric detection



Simultaneous Analysis of Sulfonylurea Herbicide Residues in

Fruit Samples using Ultrasound–Assisted Surfactant–Enhanced

Emulsification Microextraction followed by High Performance

Liquid Chromatography

Ketsarin Seebunrueng1, Yanawath Santaladchaiyakit

2, and Supalax Srijaranai

1,*

1 Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University,

Khon Kaen 40002, Thailand 2Department of Chemistry, Faculty of Engineering, Rajamangala University of Technology Isan, Khon Kaen

Campus, Khon Kaen 40000, Thailand


An ultrasound–assisted surfactant–enhanced emulsification microextraction (UASEME) combined

with high performance liquid chromatography–diode array detection was developed for

determination of sulfonylurea herbicide (SUH) residues in fruits. The studied herbicides are

thifensulfuron−methyl, metsulfuron−methyl, rimsulfuron, tribenuron–methyl and

primisulfuron−methyl. Surfactant was used as emulsifier in UASEME, it can accelerate the

formation of fine droplet of extraction solvent in aqueous solution under ultrasound energy, thus

short extraction time was obtained. Several experimental parameters, including type and volume of

the extraction solvent, type and concentration of surfactant, salt addition, ultrasound extraction

time and centrifugation time were optimized. QuEChERS (quick, easy, cheap, effective, rugged,

and safe) method was applied for sample preparation of fruit samples (apple, pineapple and

watermelon) before UASEME and analysis. Under the optimum conditions; 250 µL of chloroform

(as extraction solvent), 0.5 mmol L−1

Tween 20 (as emulsifier), sonication time for 3 min and

centrifugation at 3500 rpm for 5 min; linearities were obtained in the range of 5 to 100 ng mL−1

and high enrichment factors (EFs) were 76 to 166. Good precisions with the relative standard

deviations (RSDs) were less than 6.4%. Low LODs of the studied SUHs in fruit samples were in

the range of 0.02–2 µg kg−1

which are below the maximum residue level (MRL) established by

EU–MRL. No contamination by the studied SUHs in samples was observed and good recoveries

ranging from 79 to 105% was obtained.

Keywords Sulfonylurea herbicides; Ultrasound–assisted surfactant–enhanced emulsification

microextraction; High performance liquid chromatography; Fruit



Fluorescence Silver Nanoclusters as A Selective Sensor for the

Detection of Pb2+

Niratcharin Kawanan1, Wittaya Ngeontae

1, 2, 3,*



Khon Kaen 40002, Thailand 3Center of Excellence for Environmental and Hazardous Waste Management (EHWM), Bangkok 10330,

Thailand


A new, simple, and sensitive fluorescent sensor for detecting Pb2+

was developed based on silver

nanoclusters (AgNCs). A water-soluble AgNCs can be synthesized by using polymethacrylic acid

(PMAA) as a template and a reducing agent. The AgNCs acquired showed steady, selective, and

highly sensitive detection of Pb2+

. In the presence of Pb2+

, the fluorescence intensity of AgNCs (λex

= 510 nm, λem = 585 nm) increased as a linear function of Pb2+

concentrations. The parameters that

could possibly affect the fluorescence enhancement of AgNCs by Pb2+

were investigated. The

preliminary results showed that the proposed sensor could respond to the concentration of Pb2+

lower than 1 M with a response time faster than 1 min.

Keywords Chemical sensors; Fluorescence sensors; Silver nanoclusters



Simultaneous Determination of Ascorbic Acid and Uric Acid

using Porous Graphitized Carbon Monolith Modified with

Glassy Carbon Electrode

Siriboon Mukdasai

1, Eric Moore

2, Mila Pravda

3, Xiaoyun He

4, Nattaya Butwong

5, Jeremy D. Glennon

3*,

Supalax Srijaranai1*

1 Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University,

Khon Kaen 40002, Thailand 2 Life Science Interface, Tyndall National Institute, Cork, Ireland

3 Department of Chemistry and Analytical, Biological Chemistry Research Facility, University College Cork,

Cork, Ireland 4 National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland

5 Department of Applied Chemistry, Faculty of Science and Liberal Arts, Rajamangala University of

Technology Isan, Nakhon Ratchasima, Thailand * E-mail: [email protected]

In this work, glassy carbon electrodes (GCE) was modified with porous graphitized carbon

monolith (CM) as a new nanomaterials. Scanning electron microscopy (SEM), electrochemical

impedance spectroscopy (EIS) and cyclic voltammetry (CV) was employed for the surface analysis

of the modified electrode. The modified CM/GCE was used as working electrode for the

simultaneous determination of ascorbic acid (AA) and uric acid (UA) by cyclic voltametry. Two

well resolved peaks were obtained at -39 mV and +233 mV with flat base-lines for oxidation of

AA and UA, respectively. Under the optimum conditions, the oxidation peak current was linearly

dependent on AA and UA concentration in the range 0.195-4.04 mM and 0.094-1.90 mM, with the

correlation coefficients (R2) greater than 0.997. Detection limits (S/N=3) were found 0.39 µM and

0.15 µM for AA and UA, respectively. The CM/GCE showed high sensitivity, good reproducibility

and long-time stability to at least 1 month without significant loss of electrochemical signal.

Keywords Porous graphitized carbon monolith; Ascorbic acid; Uric acid; Modified glassy carbon

electrode



Comparison of Kjeldahl and Combustion Methods for

Determining Protein Contents of Some Food Using Data from

A Proficiency Testing Project

Wachira Singkong1*, Anek Halee

1, Boonyakrit Rattanapun

1

1 Department of Food Science and Technology, Faculty of Science and Technology,

Kamphaengphet Rajabhat University, Kamphaengphet, 62000, Thailand


The Kjeldahl method, which relies on the conversion of protein nitrogen into the ammonium ion by

boiling sulfuric acid in the presence of a catalyst, and the Combustion method, which relies on the

combustion of the test material and measurement of the resulting elemental nitrogen for the

measurement of protein in some food are milk powder, flour and feeding stuffs. This paper

describes part of a study to provide a definitive comparison of the results of the two methods. The

preliminary work reported here is based on historical data collected from a proficiency testing

project, and it will be followed by a designed experiment. Data used in this study were taken from

Taiwan Accreditation Foundation (TAF), a proficiency testing scheme organised by Department of

Science Service (DSS), Bangkok, Thailand. A range of test material types are offered for the

determination of nitrogen in this scheme. Many laboratories using the Kjeldahl or Combustion

methods participate in these rounds. Data from 5 rounds were considered. For each round the results

of the participants were segregated according to method used. Preliminary studies showed no

discrimination between identifiable variations within the two methods under consideration, so the

results of all variants of the Kjeldahl method were lumped together, as were those of all variants of

the Combustion method. The results of this empirical study show that overall there is a clear bias

between the methods, with the Combustion method normally providing a slightly higher result than

the Kjeldahl method. This finding is consistent with previous studies and with the generally

accepted explanation, namely that nonprotein forms of nitrogen are converted into elemental

nitrogen in the Combustion method. However, the bias between the methods can vary significantly,

among both food types and individual examples of a particular type. The methodology of observing

for bias between Kjeldahl and Combustion methods is critically discussed.

Keywords Kjeldahl method; Protein determination; Proficiency testing; Combustion method



Surfactant-solvent Based Emulsification Microextraction and

High Performance Liquid Chromatography for Analysis of

Benzimidazole Anthelmintics in Milk Samples

Yanawath Santaladchaiyakit1,

*, Supalax Srijaranai2

1Department of Chemistry, Faculty of Engineering, Rajamangala University of Technology Isan, Khon Kaen

Campus, Khon Kaen 40000, Thailand


Chemistry. Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand


A surfactant-solvent based emulsification microextraction (SSEME) method has been developed

for the extraction and preconcentration of benzimidazole anthelmintics (i.e., oxfendazole,

mebendazole, albendazole, and fenbendazole) followed by high performance liquid

chromatographic analysis in milk samples. Triton X-114 (as emulsifier or carrier), acetonitrile

(disperser solvent), and 1-octanol (extraction solvent) were used for SSEME. The SSEME was

carried out in 10-mL sample solution using a mixture of 0.5% (w/v) Triton X-114, 125 µL of

acetonitrile, and 60 µL of 1-octanol. Under the selected conditions, preconcentration factor was

achieved in the range of 21 – 28. For milk analyses, linearity was obtained in the range of 10 – 200

µg/L with the coefficient of determination (R2) greater than 0.996. Limits of detection were

between 2.6 – 10.0 µg/L. High precisions (intra-day, n=6 and inter-day, n=6×3) in the studied

samples with the relative standard deviation (RSD) lower than 8.8% were achieved. Good

recoveries for the spiked target benzimidazoles (25, 50, 100 and 150 µg/L) were also obtained in

the range of 77.0 – 114.1%. The proposed SMEME method has been proven to be simple,

effective and reliable for the analysis of target analytes in the samples studied.

Keywords Surfactant-solvent based emulsification microextraction; Benzimidazole anthelmintics;

High performance liquid chromatography; Milk



Vortex-assisted Surfactant-Enhanced-Emulsification

Microextraction using a Low Density Extraction Solvent

Combined with HPLC for the Determination of Neonicotinoid

Pesticides

Jitlada Vichapong,a,*

Rodjana Burakham,b Supalax Srijaranai,

b

aChemical Creativity and Innovation Research Unit, Department of Chemistry, Faculty of Science,

Mahasarakham University, Mahasarakham 44150, Thailand bMaterials Chemistry Research Unit, Department of Chemistry and Center for Innovation in Chemistry,

Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand


A simple microextraction procedure based on vortex-assisted surfactant-enhanced-emulsification

microextraction using a low density extraction solvent (VASEME-LDS) is investigated for the

determination of neonicotinoid pesticides. According to this method, the organic extraction solvent

(octanol) was dispersed into the aqueous samples by the assistance of surfactant (sodium dodecyl

sulfate) and vortex agitator. Other experimental parameters affected the extraction efficiency,

including the kind and concentration of salt, concentration and volume of HCl, kind and

concentration of surfactant and its volume, kind and volume of extraction solvent, vortex time and

centrifugation time, were also optimized. Five neonicotinoid pesticides, including acetamiprid,

clotianidin, nitenpyram, imidacloprid, and thiamethoxam, were separated within 8 min using

Atlantis dC18 column (4.6 mm i.d.×150 mm, 5 μm particle diameter), using a mobile phase of

25% acetonitrile in water, at a flow rate of 1.0 mL min–1

, and photodiode array detection at 254

nm. Under the optimum extraction conditions, high enrichment factors (EFs) were in the range of

20 – 100. The limits of detection (LODs), calculated as three times the signal-to-noise ratio (S/N),

were in the range of 0.1 – 0.5 μg L–1

. Good recoveries and repeatability of the method for

neonicotinoid pesticides were also obtained. The proposed method was applied to determine

neonicotinoid pesticide residues in surface water and fruit juice samples.

Keywords Vortex-assisted surfactant-enhanced-emulsification microextraction; HPLC;

Neonicotinoid pesticides; Extraction



Analysis of Odor Volatile Components of Citharexylum

spinosum Flowers by Using Solid Phase Microextraction-Gas

Chromatography-Mass Spectrometry

Ae Mar, Patcharee Pripdeevech*

Program of Applied Chemistry, School of Science, Mae Fah Luang University, Chiang Rai, 57100, Thailand


Odor volatile compounds of fresh Citharexylum spinosum flowers were extracted by using solid

phase microextraction prior analysis by gas chromatography-mass spectrometry. Three fibers

including PDMS, CAR/PDMS and DVB/CAR/PDMS were chosen for extraction of C. spinosum

odor constituents. Fifty-two odor volatile components were identified among these fibers. Eighteen

compounds were detected with PDMS fiber. The key odor volatiles were methyl benzoate, phenyl

ethyl alcohol and 2-phenyl ethyl acetate while thirty seven constituents were found when using

CAR/PDMS fiber with the major compounds of octen-3-ol, methyl benzoate, phenyl ethyl alcohol

and 2-phenyl ethyl acetate. For DVB/CAR/PDMS fiber, thirty compounds were investigated. The

major volatiles were octen-3-ol, methyl benzoate, phenyl ethyl alcohol, methyl salicylate and 2-

phenyl ethyl acetate. Different contents of volatile components of C. spinosum flowers were

related to composites on each fiber. The DVB/CAR/PDMS fiber was considered to be the best

fiber for extraction of odor volatiles of fresh C. spinosum flowers due to the highest number of

volatile components compared to other fibers. It is noted that the solid phase microextraction

technique is more sensitive to extract the volatile components which played the significant role as

the key scent in C. spinosum flower.

Keywords Citharexylum spinosum; Solid Phase Microextraction; Gas Chromatography-Mass

Spectrometry; DVB/CAR/PDMS; Odor volatiles



A Solid-State Sensor based on

Tris(2,2’bipyridyl)ruthenium(II)/polytyramine Modified

Electrode: Characterization and application for

chlorpheniramine maleate electroanalysis

Mohammed M. Al-Hinai1*

, Emad A. Khudaish1

Sultan Qaboos University, College of Science, Department of Chemistry, PO Box 36, PC 123, Muscat, Oman.


A solid-state sensor based on Polytyramine film deposited at glassy carbon electrode doped with

tris(2,2‟-bipyridyl)Ru(II) complex (Ru/Pty/GCE) was constructed electrochemically. The surface

morphology of the film modified electrode was characterized using electrochemical and surface

scanning techniques. A redox property represented by [Ru(bpy)3]3+/2+

couple immobilized at the

Pty moiety was characterized using typical voltammetric techniques while XPS data and AFM

images prove its grafting. The constructed sensor showed high sensitivity, stability and

reproducibility towards electrochemical measurements of CPM. The detection limit (S/N=3) was

0.4 M with a linear dynamic range between 2.0 M to 20.0 M using differential pulse

voltammetry. The recovery of tested samples (syrup and tablets) under the experimental conditions

was ranged between 96% and 105%. Thermodynamic and kinetic parameters were also evaluated

using Koutecky-Levich plots.

Keywords: Polytyramine; electroanalysis; Thermodynamic



The Production and Selenium Speciation of Se-enriched

Kale Seedling

(Brassica oleracea var. alboglabra L.)

Sarunya Maneetong1, Sumalee Chookhampaeng

2, Anut Chantiratikul

3, Orawan Chinrasri

3,

Witphon Thosaikham1, Piyanete Chantiratikul

1*

1Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC),

Faculty of Science, Mahasarakham University, Kamrieng, Kantarawichai,

Maha Sarakham, Thailand, 44150. 2Department of Biology, Faculty of Science, Mahasarakham University, Kamrieng, Kantarawichai,

Maha Sarakham, Thailand, 44150. 3Department of Agricultural Technology, Faculty of Technology, Mahasarakham University,

Kamrieng, Kantarawichai, Maha Sarakham, Thailand, 44150.

* Email: [email protected] and [email protected], Tel: +66-8-7173-5444

Kale (Brassica oleracea var. alboglabra L.) seedlings were selected for cultivation as Se-enriched

vegetable by a hydroponic system. Se-enriched kale seedlings were grown in Hoagland‟s solution

supplemented with 5, 10, 15, 30 and 45 µg Se (IV) mL-1

from sodium selenite for 15 days and

harvested every 5 days. Cultivation of kale seedlings with 45 µg Se mL-1

inhibited the growth rate

and Se accumulation. However, total Se concentrations of all Se-supplemented treatments were

higher than that of control treatment. The highest Se concentration accumulated by kale

approximately 400 µg Se g-1

(expressed as Se in dry matter) was obtained in the kale which was

grown with 30 µg Se mL-1

in solution. Se Speciation studies indicated that the predominant forms

of organic Se are selenomethionine (SeMet), Se-methylselenocysteine (SeMC) and unknown which

were identified in 0.1 M HCl in 10% methanol extracts by ion pairing reversed phase HPLC-ICP-

MS. Moreover, almost 100% of Se in the extract was found to be non-metabolized selenite when

harvested longer than 15 days. Thus, it is possible to produce Se-enriched seedling with the method

proposed

Keywords Se-enriched kale seedling; Se speciation; reversed phase HPLC-ICP-MS



Monitoring of Styrene using SS/Zn/PEG Sol-Gel SPME Fiber in

Food from Polystyrene Container

Pimsuda Pansa-Ngat 1,2,3

, Panote Thavarungkul 1,2,4

, Proespichaya Kanatharana1,2,3

,

Chongdee Thammakhet1,2,3

*

1Trace Analysis and Biosensor Research Center,

2Center of Excellence for Innovation in Chemistry,

3Department of Chemistry,

4Department of Physics, Faculty of Science,

Prince of Songkla University, Songkhla 90112, Thailand


A polyethylene glycol fiber developed by electrodepositing porous Zn film on stainless steel wire

substrate followed by coating with polyethylene glycol sol-gel (SS/Zn/PEG sol-gel fiber) was

exploited in the determination of styrene in food contained in polystyrene containers. The

reduction potential and charge utilized for the electrodeposition were -1.4 V and 3.0 C,

respectively. The porous Zn film fiber was then dipped into PEG sol-gel and the coating times of

this PEG sol-gel onto the porous Zn film fiber was also studied. The scanning electron micrographs

of the developed fiber surface revealed a highly porous structure. The extraction efficiency of the

developed fiber to styrene residue was then investigated using headspace solid-phase

microextraction (HS-SPME) method and the quantitative analysis was performed using gas

chromatography-flame ionization detection (GC-FID).

Keywords Solid-phase microextraction; Polystyrene packaged food; Styrene residue




Highly Selective Colorimetric Sensor for Fe2+

based on

Water-Soluble Silver Nanoclusters

Kanokwan Chaiendoo1, Wittaya Ngeontae

1, 2, 3,*



Khon Kaen 40002, Thailand 3Center of Excellence for Environmental and Hazardous Waste Management (EHWM), Bangkok 10330,

Thailand


A new colorimetric sensor for detecting Fe2+

was proposed based on the water-soluble silver

nanoclusters (AgNCs). AgNCs were synthesized via one-pot reaction by using polymethacrylic acid

(PMAA) as both a template and a reducing agent. The as-prepared AgNCs showed selective and

highly sensitive detection of Fe2+

over Fe3+

. Upon the addition of Fe2+

, a new absorbance spectrum

at the maximum wavelength of 447 nm increased as a linear function of Fe2+

concentrations. The

parameters that could possibly affect the sensor sensitivity by Fe2+

were investigated. Under the

optimum conditions, Fe2+

could be determined in the range of 5-100 M with detection limit of 0.76

M and the relative standard deviations for ten replicate was only 0.67 %.

Keywords Chemical sensors; Colorimetric sensors; Silver nanoclusters



Novel Solid-Phase Microextraction Coupled with LC-MS

Determination of Tetracycline from Waste Water

K. Khaunmeung1, O. Chienthavorn

1

1Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of

Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand.

Tetracycline is an antibiotic drug. Due to its extensive and effective treatments to many diseases, it

is widely used in humans and livestock. Excessive usage of the drug leads to environmental

leachate through humans and animals excretion, causing agricultural impacts of microbes in the

environment. Research study has shown antimicrobial resistance of the microbes to the drug.

Measurement of the drug in the environment can be helpful to monitor the risk of creating and

spreading the resistance. Due to a very low concentration of tetracycline in water, sensitivity and

selectivity of analysis method is needed. In this study, C-18 silica monolithic material was

fabricated via a sol-gel method, and because of its higher surface area than that of classical solid-

phase, the material was used as an adsorbent in extraction and preconcentration steps of waste

water samples, resulting the preconcentration factor of 50. With the very high active surface the

mass required for adsorption is lowered, thus reducing the consumption of organic eluent and time

required for preconcentration step. The monolithic structure was verified by using a scanning

electron microscope (SEM). Three drug compounds in tetracycline group, namely oxytetracycline,

chlortetracycline and tetracycline was extracted and preconcentrated using the developed solid

sorbent prior to high performance liquid chromatography coupled with mass spectrometric

measurement.

Keywords: monoliths; tetracycline; extraction; waste water



Solid-Phase Extraction Using Surfactant-Modified Alumina

Combined with Spectrophotometry for

Determination of Carbaryl

Nisakorn Namwong, Rodjana Burakham*

Materials Chemistry Research Unit, Department of Chemistry and Center for Innovation in Chemistry,



A simple solid-phase extraction (SPE) procedure using surfactant-modified sorbent was developed

for preconcentration of carbaryl prior to spectrophotometric detection. Alumina was modified with

sodium dodecylsulfate (SDS) before packing in a 1.0 mL syringe cartridge. SDS was effectively

sorbed on the positively charged alumina surface in an acidic medium, and presented potential for

preconcentration of carbaryl. The sample solution was passed through the SPE cartridge and then

eluted with an appropriate eluent. Detection of carbaryl was performed via spectrophotometry at

480 nm using 2-napthylamine-1-sulfonic acid (ANSA) as derivatizing reagent. The experimental

parameters, including amount of sorbent, sample volume, type and volume of eluent, were

optimized. Under the selected condition, linear calibration graph was observed in the range of 0.1-

10.0 mg L-1

with the correlation coefficient of 0.9984. Good precision was obtained with the

relative standard deviation (RSD) of less than 4%. Applicability of the proposed procedure was

studied by determination of carbaryl in water and fruit juice samples.

Keywords Carbaryl; Spectrophotometry; Surfactant modified alumina; Solid phase extraction



Comparison of Retention and Selectivity of Monolithic Silica

Stationary Phase Modified with C18 and Amino Moieties and

C14 Embedded Amino Group for Mixed-Mode Liquid

Chromatography

Wanvisa Rattanangam1, Puttaruksa Varanusupakul

1*

1Chromatography and Separation Research Unit, Department of Chemistry, Faculty of Science,

Chulalongkorn University, Bangkok 10330, Thailand *E-mail: [email protected]

A monolithic silica capillary column for a mixed-mode liquid chromatography can be prepared with

several modification methods. This work showed two different modification methods which are one

step and two step modifications. The one step method modified a monolithic capillary column by a

mixture of octadecylmethoxysilane and aminopropyltrimethoxysilane. In the two step method, a

monolithic capillary column was first modified with glycidoxypropyltrimethoxysilane and followed

by tetradecylamine. The retention and selectivity of both columns were determined by Tanaka‟s test

which consisted of hydrophobicity, shape selectivity, ion exchange and silanophilic interaction.

Keywords HPLC; monolithic column; mixed-mode; selectivity



The Determination of Dithiocarbamate Herbicides using Metal-

Nanoparticles Modified Screen Printed Electrode

Kanokwan Charoenkitamorn1, Weena Siangproh

2*, Orawon Chailapakul

1,3*


Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand 2Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana,

Bangkok 10110, Thailand 3Center of Excellence on Petrochemical and Mateials Technology, Chulalongkorn University, Patumwan,



Metal-nanoparticles (MNPs) are effective materials used as catalytic tools to improve the

sensitivity. In this work, we are interested in the determination of dithiocarbamate herbicides

including thiram and disulfiram using screen printed electrode (SPCE) modified with MNPs. The

MNPs modified SPCE was prepared by the electrodeposition method. The optimal condition for

electrodeposition such as deposition potential, deposition time and concentration of metal solution

were –0.6 V, 100 s and 10 mM respectively. The morphology analysis of MNPs modified SPCE

was investigated using scanning electron microscope (SEM). It was found that nanoscale of metal

particles was obtained at SPCE surface. The developed electrode was used to determine thiram and

disulfiram by differential pulse voltammetry. Compared to an unmodified SPCE, the MNPs

modified SPCE gives higher electrochemical sensitivity for thiram (about 15 folds). For the

preliminary results, we suggest that the developed electrode is an effective sensor for determination

of dithiocarbamate herbicides. The analytical performance will be discussed.

Keywords metal nanoparticles; screen printed electrode; dithiocarbamate; thiram; disulfiram



Simultaneous Determination of Iron Chelator Deferiprone and

Creatinine in Human Urine by High Performance Liquid

Chromatography

Phoomirut Nusuwan, Kamonchanok Trakuljaidee, Piyada Jittangprasert*

Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok, 10110, Thailand


A simple and fast high-performance liquid chromatographic method has been developed for the

simultaneous analysis of iron chelator deferiprone and creatinine in human urine. Chromatographic

analyses were carried out on a C18 column employing gradient elution of methanol and 10 mM

phosphate buffer (pH 6.0) containing 2 mM EDTA as the mobile phase. Direct UV absorption at

234 and 275 nm were used for detection of creatinine and deferiprone, respectively. The method

developed for simultaneous separation of deferiprone and creatinine showed that calibration curves

for both compounds were linear with correlation coefficients (R2) > 0.999. The limit of detections

(LOD; 3SD) of deferiprone and creatinine were 4.19 and 0.70 g/ml, respectively. The results of

precisions were satisfied giving %RSD < 1.23 for repeatability experiments and < 3.70 for

reproducibility experiments. The average recoveries (n = 3) were in the range of 98.0-110%. This

method was successfully applied for the simultaneous separation of deferiprone and creatinine in

human urine samples and provided the separation of both compounds from endogenous matrices in

urine within 7.5 minutes by using only dilution as sample pretreatment before analysis.

Keywords Deferiprone; creatinine; urine; high performance liquid chromatography



A Survey of UV Filters in Sunscreen Products and Development

of a HPLC Method

Noppamas Yuying1, Sudaporn Wongwan

2, Tasana Pitaksuteepong

1*

1Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University,

Phitsanulok-Nakornsawan Rd, Phitsanulok 65000, Thailand

.2Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences,

Naresuan University, Phitsanulok-Nakornsawan Rd, Phitsanulok 65000, Thailand.


All International agencies as well as Thai FDA regulated the maximum amount of UV filters

allowed to be used in sunscreen products. Most of the commercial sunscreens contain more than

one UV filters in order to achieve high UV protection. Therefore, the aims of this study were to

survey UV filters commonly used in sunscreen products and to develop high performance liquid

chromatography (HPLC) system for the simultaneous determination of the UV filters. The survey

was performed in the local hypermarkets in Thailand during August to September 2012. For

development of a HPLC method, various parameters including types of mobile phases, flow rate

and column temperature were investigated on a Luna C18 Column (250 x 4.6 mm, i.d. 5 µm

particle size) at UV detection 325 nm with an injection volume of 20 µl. The result showed that the

commonly found UV filters were: benzophenone-4, bis-ethylhexyloxyphenol

methoxyphenyltriazine, butyl methoxydibenzoylmethane, ethylhexyl dimethyl PABA,

ethylhexylmethoxycinnamate, ethylhexyl salicylate, ethylhexyl triazone, homosalate, methylene

bis-benzotriazolyl tetramethylbutylphenol and octocrylene. The simultaneous separation of ten UV

filters was accomplished when using acetonitrile: ethyl acetate: water (95:5:2, v/v/v) with flow rate

1.0 ml/min. The column temperature was controlled at 25 °C. Total analysis time was 85 min.

Keywords Sunscreen; UV filters; HPLC



Silver Nanodendrite Modified Electrode for Hydrogen Peroxide

Detection

Jittima Choosang

1,2 , Apon Numnuam

1,2* , Proespichaya Kanatharana

1,2 , Panote Thavarungkul

1,3

1Trace Analysis and Biosensor Research Center,

2Department of Chemistry,

3Department of Physics

Faculty of Science, Prince of Songkla University, Thailand 90112


Silver nanodendrite modified gold electrode (Ag/Au) was successfully synthesized by

electrodeposition of Ag from AgNO3 solution on a gold electrode. The morphology of the

nanostructure was characterized by scanning electron microscopy (SEM). The electrochemical and

catalytic properties of the Ag dendrite were examined by cyclic voltammetry and amperometry.

The Ag dendrite exhibited enhanced electroreduction of hydrogen peroxide. When used as a sensor

for H2O2 detection, the Ag/Au electrode provided a 1.9-fold higher sensitivity than that of a bare

gold electrode.

Keywords Silver nanodendrite; Hydrogen peroxide sensor; Electrodeposition



Antioxidant Activity of Phenolic Extract of Concentrate Juice

obtained from “Mao” Fruits (Antidesma thwaitesianum Muell.

Arg.) and Their Effect of Thermal Stability

Thitiya Sripakdee, Ratana Mahachai and Saksit Chanthai*


Khon Kaen University, Khon Kaen 40002, Thailand


The “Mao” compiled fruits (Antidesma thwaitesianum Muell. Arg.) found in wild tropical forests

are used as commercially available products of concentrate juice and local fruit wine in Thailand,

particularly its concentrate juice contains a very rich source of antioxidants including polyphenols.

The present study was aimed to determine phenolic content and antioxidant activity in the juice

sample. Total phenolic content was determined using Folin-Ciocalteu assay. The antioxidant

activity was evaluated by four different spectrophotometric methods including 1,1-diphenyl-2-

picryl-hydrazyl (DPPH), 2,2´-azinobis(3-ethylbenzothiazoline 6-sulphonate (ABTS), N,N-dimethyl-

p-phenylenediamine dihydrochloride (DMPD) and ferric reducing-antioxidant power (FRAP). It

was found that the phenolic content of the juice was 5121.3 ± 43.3 mg GAE/100 mL sample. Their

antioxidant activity against DPPH assay was 2655.6 ± 31.3 mg BHT/100 mL sample. ABTS and

DMPD ones gave 1027.3 ± 1.3 and 281.9 ± 9.8 mg Trolox/100 mL sample, respectively. While

FRAP assay gave 51.6 ± 0.02 mM Fe2+

/100 mL sample. In addition, thermal stability of total

phenolic compounds of the juice sample was also investigated by heating at various temperatures

(60-100C) for 30 min prior to analysis. It was found that the antioxidant activity of the juice was

not affected at 60 C, but loss of the antioxidant activity of 3.02 % at 80 C was observed as the

phenolic contents decreased to be 6.22 %. Thus, the influence of heat on the antioxidant activity of

the fruit juice was also a susceptible factor due to labile stability of phenolic compounds.

Keywords: Antidesma thwaitesianum Muell. Arg., antioxidant activity, total phenolic compounds,

thermal stability



High Performance Liquid Chromatography – Photodiode Array

Detection (HPLC-DAD) for Quantitative Analysis of Cefazolin

in Human Bone

Warawut Tiyapongpattana1*, Kittigan Suwannasaroj

1, Pongpaibool Krajubngoen

2 and Chayanin Angthong

2

1 Department of Chemistry, Faculty of Science and Technology, Thammasat University, Khlong-Luang,

Pathum-thani, 12121, Thailand 2 Department of Orthopaedics, Faculty of Medicine, Thammasat University, Khlong-Luang,

Pathum-thani, 12121, Thailand

*E-mail: [email protected], [email protected]

High-performance liquid chromatography-photodiode array detection (HPLC-DAD) method for

quantitative analysis of cefazolin in distal femur and proximal tibia was developed. Bone fragments

were placed in polypropylene tubes with phosphate-buffered saline and salicylic acid (internal

standard). The extraction was carried out using horizontal shaker for two hours. Afterwards, the

sample was partitioned by centrifugation and the supernatant was transferred into HPLC

autosampler vial. For component separation, the method utilized a C18 column with an aqueous

mobile phase of acetonitrile and 0.1 % (v/v) formic acid isocratic at a flow rate of 1 mL/min. Under

the optimal condition, validation of the method demonstrated a good sensitivity, precision and

accuracy. The calibration curves were obtained for a plot between the area ratio with the concentration of

cefazolin and salicylic acid, ranging from 0.05 – 70 µg/mL (r2 > 0.9995). The limits of detection and

quantitation were 0.03 and 0.05 µg/mL, respectively. The developed method gave satisfactory

precision in terms of repeatability and reproducibility with RSD of 2.17 % and 4.70 % (n=10),

respectively. The accuracy of the method was reported as the recovery of nominal spiked amounts

versus measured component concentrations. The recoveries were in the range of 103.29+2.30 –

106.94+0.01 %. The proposed method has been applied to investigate the intraoperative

concentration of cefazolin in subchondral bone of distal femur and proximal tibia in total knee

arthroplasty.

Keywords High-performance liquid chromatography-photodiode array detection (HPLC-DAD);

Cefazolin; Distal femur; Proximal tibia; Total knee arthroplasty;



Monolith Based Immobilized AChE Flow-Through Reactor

for Heavy Metal Determination

Parawee Rattanakit1*, Saisunee Liawruangrath

2

1School of Science, Walailak Universtiy, Nakhon Si Thammarat 80161, Thailand

2 Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand


A monolith based immobilized acetylcholinesterase (AChE) flow-through reactor has been

developed for the determination of heavy metal using flow injection spectrophotometric system.

The bioreactor was prepared inside a micro capillary column by in situ polymerization of

butylmethacrylate, ethylenedimethacrylate and 2,2-dimethoxy-1,2-diphynyletane-1-one in the

presence of 1-decanol, followed by vinylazlactone functionalization and AChE immobilization.

The detection was based on measuring inhibition effect on the enzymatic activity of AChE by

copper (II) using Ellman‟s reaction with spectrophotometric detection at 410 nm. The linear range

of the calibration graph was obtained over the range of 0.12-3.00 mg L-1

. The detection limits,

defined as 10% inhibition (I10) was found to be 0.14 mg L-1

. The repeatability was 3.35 % (n=5) for

1.00 mg L-1

of copper (II). The proposed system can be used for an alternative green analytical

chemistry.

Keywords Polymer monolith; Heavy Metal; Acetylcholinesterase; Flow-Through Reactor



Ultrasound-Assisted Surfactant-Enhanced Emulsification

Microextraction Coupled with High Performance Liquid

Chromatography for the Determination of Benzimidazole

Anthelmintics

Tittaya Boontongto1, Yanawath Santaladchaiyakit

2, Rodjana Burakham

1*

1Materials Chemistry Research Unit, Department of Chemistry and Center for Innovation in Chemistry,

Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand 2Department of Chemistry, Faculty of Engineering, Rajamangala University of Technology Isan,

Khon Kaen Campus, Khon Kaen 40000, Thailand


A simple ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME)

coupled with high performance liquid chromatography (HPLC) has been developed for extraction

and determination of six benzimidazole anthelmintics, including oxfendazole, albendazole,

mebendazole, flubendazole, fenbendazole and niclosamide. The separation was achieved within 12

min, using an Inertsil®ODS column (4.6 x 150 mm, 5.0 µm), with a gradient mobile phase of

acetonitrile and 0.1% (v/v) formic acid. Parameters affecting the extraction efficiency, such as kind

and volume of the extraction solvent, type and concentration of the surfactant, ultrasound

extraction time, centrifugation time and salt addition were investigated. Under the optimum

conditions using Tergitol TMN-6 and 1-octanol as emulsifier and extraction solvent, respectively,

linearity was in the range of 0.05–7.0 mg L−1 with the correlation coefficients (r

2) ranging from

0.991 to 0.997. Enrichment factors were obtained up to 64, corresponding to limits of detection

ranging from 0.001–0.007 mg L−1. Intra-day (n=8) and inter-day (n=3x4) precisions were obtained

with relative standard deviations for retention time and peak area of lower than 1% and 12%,

respectively. The proposed method was successfully applied to determine the target

benzimidazoles in milk formulae.

Keywords Ultrasound-assisted surfactant-enhanced emulsification microextraction;

Benzimidazole anthelmintic; High performance liquid chromatography



Dispersive Liquid-Liquid Microextraction and High

Performance Liquid Chromatography for Analysis of

Carbamate Insecticides

Kanchana Kongphonprom, Rodjana Burakham*

Materials Chemistry Research Unit, Department of Chemistry and Center for Innovation in Chemistry,



A simple dispersive liquid-liquid microextraction (DLLME) was developed for extraction of

carbamate insecticides prior to high performance liquid chromatography with UV detection (HPLC-

UV). The carbamate insecticides studied include methomyl, aldicarb, carbofuran, carbaryl,

isoprocarb and methiocarb. Seperations were performed on a Luna 5 μm C18(2) column (150×4.6

mm), using the gradient mobile phase of methanol and 0.1% acetic acid, at a flow rate of 1.0 mL

min-1

and detection wavelength at 270 nm. Parameters affecting the DLLME performance such as

the kind and volume of extraction and dispersive solvents, sonication time and salt concentration

were studied. Under the optimum condition, six carbamate insecticides were successfully separated

within 12 min, the calibration curves were linear in the concentration range from 0.1 to 10 mg L-1

with the correlation coefficients (r2) varying from 0.9952 to 0.9995. The limits of detection (LODs)

based on signal-to-noise ratio (S/N) of 3, ranged from 0.15 to 300 μg L-1

.

Keywords Carbamate insecticide; Dispersive liquid-liquid microextraction; HPLC



Phthalates in Edible Oil Samples by Headspace Solid-phase

Microextraction : Effect of Temperature

Sutthirak Uansiri*, Wanna Kanchanamayoon

Department of Chemistry, Faculty of Science, Mahasarakham University,

Maha Sarakham 44000, Thailand


The determination of four phthalates, dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl

phthalate (DBP), di(2-ethylhexyl) phthalate (DEHP), in edible oils sample were investigated based

on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography (GC)

using a polydimethylsiloxane-divinylbenzene (PDMS-DVB) fiber. Analytes were separated on GC

following oven temperature was set at 150 °C, increased to 270 °C at 15 °C/min and kept at 270 °C

for 15 min. Extraction temperature is a parameter for the extraction efficiency. Several extraction

temperatures were investigated to obtain the behavior of phthalates in the range of 50-90 °C. It was

found that the maximum peak area of phthalates was obtained at 80 °C of extraction temperatures.

Keywords Phthalate; Headspace Solid-phase Microextraction



Method Development for Determination of Fe(II) by Paper

based Devices with Colorimetric Sensing in Water Sample

Benjawan Ninwong1*, Rungnapa Pimsen

1, Wijitar Dungchai

2

1

Department of Chemistry, Faculty of Science and technology, Nakhon Si Thammarat Rajabhat

University, Nakhon Si Thammarat,80280, Thailand. 2 Department of chemistry, Faculty of Science, King Mongkut’s University of Technology Thonburi,

Bangkok, 10140, Thailand.


A colorimetric method has been developed for determination of Fe(II) by paper based devices. The

analytical device fabricated by solid wax printing on filter paper with was indicated that

hydrophobic zone. Fe(II) was detected by the reaction of Fe(II) with 1,10-phenanthroline in the

red/orange ferroin complex [Fe(phen)3]2+

formed. The color in detection zone immediately change

after addition of Fe(II) that was depending on the concentration. The effects of other metal ions as

sources of interference on paper based devices were investigated and so do not interfere. The color

intensity of detection zone was measured using a scanner and conjunction with ImageJ software in

gray mode. Operational parameters such as channels size, pH of sample, complexation time and

reagent volume were optimized. Under the optimum conditions, the analytical characteristics were

studied. The limit of detection was 0.02 mg L-1

. The proposed method provide rapid, sensitive and

selective for detection of Fe(II) in water sample of Nakhon Si Thammarat, minimal reagent

consumption, low cost and is especially suitable for on-site environmental monitoring.

Keywords Fe(II); Paper based device; Solid wax printing; Colorimetric sensing



Spectrophotometric Method for Determination of Co(II) using

Nitroso-R Salt as Complexing Agent

Nongkran Duangsin, Uthai Sakee, Senee Kruanetr*


Mahasarakham University 44150, Thailand

* E-mail: [email protected]

A spectrophotometric method for determining Co(II) using nitroso-R salt (disodium-1-nitroso-2-

napthaol-3,-6-disulphonate) as complexing reagent was proposed. The procedure is based on the

reaction of Co(II) with nitroso-R salt in phosphate buffer pH 6.5 forming an orange-red complex

with a maximum absorption wavelength of 408 nm. Under the optimum conditions, the calibration

graph of Co(II) was linear in the range of 0.005-7.0 mg L-1

with a regression equation of y =

0.0544x-0.0023 and correlation coefficient (r2) of 0.9995. The repeatability and reproducibility are

reported as a percentage of the relative standard deviation calculated from 11 replicates of three

concentrations (0.005, 3 and 7 mg L-1)

were 2.64, 0.25 and 0.078 for repatability and 4.23, 0.29 and

0.13 for reproducibility respectively. The method was satisfactorily applied for determination

Co(II) in water samples with the percentage recoveries in range of 92.40 to 97.80.

Keywords Spectrophotometric; Nitroso-R salt; Co(II)



In-Syringe Floating Dispersive Liquid-Liquid

Microextraction (IF-DLLME) Coupled to High Performance

Liquid Chromatography for Determination of Sulfonylurea

Herbicides in Water Samples

Niphaphon Ngaosri, Supalax Srijaranai*

Materials Chemistry Research Unit, Department of Chemistry and Center of Excellence for Innovation in

Chemistry, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand


A rapid and sensitive method has been developed for determination of sulfonylurea herbicides in

water samples by using in-syringe floating dispersive liquid-liquid microextraction (IF-DLLME)

coupled to high performance liquid chromatography with diode array detection. Seven sulfonylurea

herbicides studied are thifensulfuron-methyl, metsulfuron-methyl, chlorsulfuron, rimsulfuron,

bensulfuron-methyl, tribenuron-methyl and primisulfuron-methyl. These compounds were

successfully separated using reversed phase HPLC within 35 min. Parameters affecting the

extraction efficiency, such as type and volume of extraction solvent and disperser solvent, vortex

extraction time and pH of sample were investigated and optimized. A 10-mL syringe was used as

an extraction and preconcentration container. The low density solvent, 1-octanol, was used as the

extraction solvent. Ethyl acetate was used as dispersive solvent. Under the optimum conditions,

high enrichment factors (EF) in the range between 112 and 268 were obtained, good linearities

were obtained in the range of 1 µg L-1

to 5000 µg L-1

with the correlation coefficients higher than

0.9990 and limits of detection (LODs) ranged from 0.1 µg L-1

to 0.5 µg L-1

. The precision

evaluated as the relative standard deviation (RSD) was less than 4.49 %. The present method was

successfully applied for the determination of sulfonylurea herbicide in water samples with

recoveries were 89-104%.

Keywords In-syringe floating dispersive liquid-liquid microextraction (IF-DLLME); Sulfonylurea

herbicides; High performance liquid chromatography (HPLC); Water samples



Highly Sensitive Excimer-switch Off Emission Toward Hg(II)

and Cu(II) Sensor Bearing Pyrenylacetamide Subunits

Thamon Puangsamlee1, Peeraporn Kammalun

1, Yordkhuan Tachapermpon

1, Kanjarat Suksat

2, Chantana

Wainiphithapong1, Nantanit Wanichacheva

1*

1Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand

2Chemistry Program, Faculty of Science and Technology, Nakorn Pathom Rajabhat University, Nakorn

Pathom 73000, Thailand

* E-mail: [email protected], [email protected]

A new fluorescent sensor, compound I, based on multidentate sulfide-containing ligand possessing

two pyrenylacetamide moieties covalently bound to 2-[4-(2-aminoethylsulfanyl)butylsulfanyl]-

ethanamine was prepared and investigated for its sensing behaviors. The sensor exhibited a

selective ON-OFF type sensing toward Hg2+

and Cu2+

ions, indicated by efficient quenching of the

excimer bands of pyrene at 481 nm. The sensor provided the change in fluorescence signal in the

visible regions and offered high Hg2+

- and Cu2+

- selectivity by discriminating various foreign metal

ions such as Ag+, Ba

2+, Ca

2+, Cd

2+, Co

2+, Fe

3+, K

+, Mn

2+, Na

+, Ni

2+, Pb

2+ and Zn

2+. The sensing

detection limits are sufficient for the determination of Hg2+

and Cu2+

in drinking water.

Keywords Mercury sensor; Copper sensor; Pyrene excimer; Fluorescence sensor



Development of a Reagentless α-Ketoglutarate Biosensor Based

on Methylene blue with Chitosan-Carbon nanotube Modified

Glassy Carbon Electrode

Methee Sittijareonsawat1, Anchana Preechaworapun

2, Tanin Tangkuaram

1,3,*

1 Chemistry Program, Faculty of Science, Maejo University, Chiang Mai 50290, Thailand

2 Department of Chemistry, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok, Thailand 65000, Thailand

3 Nanoscience and Nanotechnology Research Laboratory, Faculty of Science, Maejo University, Chiang

Mai 50290, Thailand


In this research, the reagentless amperometric biosensor is constructed by co-deposited with a

methylene blue (MB) and the chitosan-carbon nanotube (CHIT-CNT) with immoblilizing a β-

nicotinamide adenine dinucleotide reduced form (NADH) and the enzyme glutamate

dehydrogenase (GLUD) on the surface of a glassy carbon electrode (GCE) for determination of α-

ketoglutarate (α-KG). The co-deposited MB/CHIT-CNT coating offered greatly enhanced

electrocatalytic activity towards the detection of produced substance (NAD+) with a potential

applied 0.7 V and amount of enzyme 0.5 unit and it showed a response time to the α-KG

concentration within 10 s. The current response is linear between 5 and 500 µM (y (µA) = 0.0006

(µA.µM

-1) + 0.0197 (R

2 = 0.9764)) and detection limit of 0.03 µM

Keywords α-Ketoglutarate biosensor; Methylene blue; Chitosan-carbon nanotube; Glutamate

dehydrogenase



Rapid Assessment of Total Particulate Chromium in Air by

Colorimetric Paper-based Analytical Device

Poomrat Rattanarat1, Wijitar Dungchai

2, David M. Cate

3, Weena Siangproh

4, John Volckense

5,*, Orawon

Chailapakul1,6,*,

Charles S. Henry3,7,*

1 Electrochemistry and Optical Spectroscopy Research Unit (EOSRU), Department ofChemistry, Faculty of

Science, Chulalongkorn University, Patumwan, Bangkok 10330,Thailand 2 Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi,

Prachautid Road, Thungkru, Bangkok 10140, Thailand 3 Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23,Wattana, Bangkok

10110, Thailand 4 School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado 80523

5 Department of Environmental and Radiological Health Sciences, Colorado State University,Fort Collins,

Colorado 80523 6 Center of Excellence on Petrochemicals and Materials Technology,Chulalongkorn University, Patumwan,

Bangkok 10330, Thailand 7 Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523

* E-mail: [email protected], [email protected], and [email protected]

Occupational human exposure to particulate metals, expecially chromium (Cr), is a vital concern

because of its numerous health effects particularly related to lung cancer and several diseases in the

respiratory system. In this work, we report a novel, simple, fast, and inexpensive method for

measuring total Cr in airborne particulate matter using a microfluidic paper-based analytical device

(µPAD) coupled with colorimetric assay. The hydrophilic areas of µPAD were divided into 3 parts

including sample reservoir, pretreatment zone, and detection zone. In the pretreatment zone,

tetravalent cerium (Ce(IV)) was used to oxidize all soluble Cr to hexavalent chromium (Cr(VI)).

For the detection zone, 1,5-diphenylcarbazide (1,5-DPC) was used as a colorimetric agent for

detecting Cr(VI). After microwave-assisted acid digestion step, digested punch was place above the

sample reservoir. Acetate buffer pH 4.5 was used for pH control and elution of Cr contained on the

punch through the detection zone. Using optimal conditions,a quantitative log-linear working range

between Cr concentration and color intensity was obtained in the range of 0.23-3.75 μg (r2 =0.998)

with a detection limit of 0.12 µg. For validation, a certified reference material containing multiple

competing metals was tested using the proposed method. Quantitative agreement was achieved

between known Cr levels in the sample and the Cr measured using the µPAD.

Keywords Total chromium, Colormetric detection, Paper-based analytical device, Tetravalent

cerium, 1,5-diphenylcarbazide



Removal of Arsenite and Arsenate Ions from Water using

Drinking Water Treatment Sludge

Pairat Srechainate and Apichat Imyim*

Department of Chemistry, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan.

Bangkok, Thailand, 10330


Drinking water treatment sludge was utilized as a low-cost alternative adsorbent for removal of

arsenite and arsenate ions from water. The sludge was characterized by X-ray diffraction (XRD),

and its chemical composition was determined using X-ray fluorescence (XRF) technique and

inductively coupled plasma optical emission spectrometry (ICP-OES). The specific surface area

was analyzed by the BET method and the point of zero charge of sludge (pHpzc) was examined by

mass titration method. In batch study, parameters affecting arsenic adsorption in aqueous medium at

room temperature including pH of solution, initial concentration of arsenic and contact time were

studied. The amount of residual arsenic in solution was determined by ICP-OES. The optimal pH

for the adsorption was 2. The amount of adsorbed arsenic decreased as the pH of the solution

increased. The equilibrium adsorption of arsenite and arsenate were obtained at 12 h. Kinetic study

of arsenic based on correlation coefficients, the experiment data fitted the pseudo-second order

(r2=0.9927-0.9999) rather than the pseudo-first order (r

2=0.9860-0.9887). Langmuir and Freundlich

adsorption isotherms were also studied. The competing anions, such as sulfate and phosphate were

evaluated.

Keywords Drinking water treatment sludge; Arsenic; Adsorption



An On-line SPE-HPLC System Using Surfactant-modified

Zeolite NaY as Sorbent for Carbamate Pesticides in

Environmental Water

Prapha Arnnok, Nopbhasinthu Patdhanagul, Rodjana Burakham*

Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University,

Khon Kaen 40002, Thailand *E-mail: [email protected]

Cetyl trimethyl ammonium bromide (CTAB)-coated zeolite NaY as a sorbent of hemimicelle/

admicelle-based solid-phase extraction (SPE) was assessed. The on-line SPE equipped with HPLC

was developed for the simultaneous preconcentration/determination of six carbamate pesticides,

including aldicarb, carbofuran, carbaryl, isoprocarb, methiocarb and promecarb. SPE column

containing 100 mg of zeolite NaY was placed in the 6-port valve and connected to the solvent delivery module. The effluent was continuously loaded to sample loop of HPLC system. Six carbamate pesticides were determined by HPLC using a LiChroCART RP-18 column with gradient

elution of methanol and 0.1% acetic acid, and detected at 270 nm. The high surface area, excellent sorption capacity and reusability of the zeolite NaY after modification with CTAB were utilized sufficiently in the on-line SPE process. The factors affecting the extraction efficiency, including sorption and desorption conditions were optimized. By rapid elution of carbamate pesticides using small volume of methanol (750 µL), the time-consuming as in conventional SPE could be avoided and amount of organic waste was reduced. The satisfactory enrichment factors were achieved in the

range of 5 to 551. The sorbent showed high sorption capacity (180 – 18,600 mg kg-1

sorbent) for

the studied pesticides and could be regenerated after SPE process. The proposed SPE-HPLC

approach was successfully applied for the analysis of carbamate pesticides in environmental water

samples (tap, surface, ground, treatment plant and rice field). The method provided detection limits

of lower than 0.14 mg L-1

.

Keywords Hemimicelle/admicelle-based solid-phase extraction; Carbamate pesticides; On-line

SPE; Zeolite NaY



Colorimetric Detection of Arsenic(III) in Aqueous Solution

Using Difluoroboron-curcumin

Sirinya Sirawatcharin, Apichat Imyim and Narong Praphairaksit

*

Department of Chemistry, Faculty of Science, Chulalongkorn University,

Pathumwan, Bangkok 10330, Thailand


One of the most critical environmental pollutions experienced nowadays is metal contamination in

water, especially those caused by arsenic thus making its determination very important. This work

presents a new colorimetric method which is simple, rapid and cost effective for the determination

of arsenic(III) in water samples. The method was based on changes in visible absorbance of

difluoroboron-curcumin (BF2-curcumin) that was prepared by the reaction of borontrifluoride

diethyletherate ((C2H5)2OBF3) and curcumin. The BF2-curcumin was dissolved in ethanol and

water (3:2 (v/v)) which yielded an orange solution with the maximum absorbance at 509 nm. In

the presence of arsenic(III), the color of BF2-curcumin solution changed from orange to blue and

the absorbance was measured by visible spectrometry at 632 nm. In this method, the concentration

of BF2-curcumin, pH of BF2-curcumin solution and response time were optimized. Under the

optimal conditions, this method provided the linear range in the order of 2-100µM with R2 above

0.99 and the limit of detection of 0.26 µM (19.77 µg L-1

), with a relative standard deviation of 2%

(n=10).

Keywords Difluoroboron-curcumin; Arsenic(III); Colorimetry




Simple Flow-Injection System for Routine Analysis of Sucrose

in Soft Drinks and Sugarcane Juices

Phanatcha Atsawawiphart, Jiraporn Duangjan, Kamonthip Sereenonchai*

Department of Chemistry, Faculty of Science and Technology, Thammasat University, Pathumthani

12120, Thailand


This work presents a simple and rapid flow-injection (FI) spectrophotometric method for

monitoring the content of sucrose in soft drinks and sugarcane juices. In order to avoid disturbance

from sample matrix such as color of samples, CO2 gas in soft drink and high turbidity of cane

juice, a suitable sample preparation was firstly employed prior measurement. Detection of sucrose

in these samples was carried out by utilizing a phenomenon of light refraction in the

spectrophotometric FI system (known as schlieren of lens effect). A substantial difference in the

refractive index at the liquid interfaces between sucrose and water carrier causes light refraction

from the usual path to the detector, resulting a peak signal. This could result in sucrose signal

detected by a spectrophotometer. Under the optimum condition, linear working range was

obtained for sucrose from 1 – 50 brix, with the correlation coefficient (r2) 0.998. Results provided

good reproducibility (RSD) of less than 1.5%, from 10 replicates of 10 brix sucrose. This FI

system was successfully applied to determine sucrose in soft drinks and sugarcane juices. Use of

schlieren phenomenon in the present FI system provided cost effective due to no chemical

employment. In addition, the proposed FI system could be applied for routine analysis of sucrose

in beverage industries and sugar refineries due to rapid determination (120 sample h-1

).

Keywords Sucrose; Flow injection; Schlieren; Soft drink; Sugarcane juice



Removal of Inorganic Arsenic from Water Using Iron(III)-

Loaded Zein Based Adsorbent

Sineephan Thanawatpoontawee, Apichat Imyim and Narong Praphairaksit

*

Department of Chemistry, Faculty of Science, Chulalongkorn University,

Pathumwan, Bangkok 10330, Thailand


Adsorption has been a popular technique for the removal of heavy metals such as arsenic,

contaminated in water. This work aims to modify zein, a major protein extracted from corn gluten,

to be a low cost adsorbent for removal of inorganic arsenic from water. The adsorbent was

prepared by the incorporation of iron(III) chloride (FeCl3) into 50% w/v of zein solution dissolved

in 70% ethanol and dropped into cold water to form adsorbent beads. After that, arsenic in water

was removed by adsorbent beads in batch method. The arsenic removal efficiency was determined

by inductively coupled plasma optical emission spectroscopy (ICP-OES). Various parameters

affecting the arsenic removal efficiency such as pH, concentration of Fe(III) and adsorption time

were optimized. Under the optimum conditions, the arsenic removal efficiency of over 70% was

achieved with the proposed technique.

Keywords Adsorption; ICP-OES; Arsenic; Zein; Iron(III)



Sequential Injection Analysis of Ferrous Ion Using Silver

Nanoclusters as Optical Sensor

Dittapong Pairoh, Kanokwan Chaiendoo, Wittaya Ngeontae, Rodjana Burakham*

Materials Chemistry Research Unit, Department of Chemistry and Center for Innovation in Chemistry.



A sequential injection analysis (SIA) was developed for determination of ferrous ion using

spectrophotometry. The detection is based on on-line reaction of silver nanoclusters (AgNCs) and

ferrous ion to form product that can be detected at a wavelength of 446 nm. The experimental

parameters affecting the sensitivity were investigated, including sequence order of operation,

volume of sequence zone, flow rate, and concentration of the reagents involved. Under the selected

condition, a linear calibration graph for ferrous iron determination was obtained over the range of

1–100 mg L-1

(r2=0.9548) with the detection limit (3σ) of 1.97 mg L

-1 and the relative standard

deviation (RSD) < 1%. The sampling frequency of 28 h-1

was obtained. The proposed system was

selective for detection of ferrous ion.

Keywords Ferrous ion; Silver nanoclusters; Sequential injection analysis



Feasibility Study of Using Silver Nanoparticles (AgNPs) for

Colorimetric Detection of Mercury (II) Ions

Chakrit Mongkontong, Maliwan Amatatongchai, Purim Jarujamrus*

Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190,

Thailand


Hg(II) is one of the most common and stable forms of mercury pollution because of its solubility in

water, which provides a pathway for contaminating large amounts of water. Therefore, it is very

important to routinely monitor Hg(II) ions levels in water. In this work, the colorimetric method

for Hg(II) detection was proposed based on the monitoring of the silver nanoparticles (AgNPs)

reduction. The visible wavelength of the plasmon absorption maximum of AgNPs occurred at

roughly 395-405 nm. The diameter size of synthesized AgNPs was 19.2 nm which was

characterized by dynamic light scattering techniques. The visible color and absorbance of AgNPs

were progressively decreased and slightly shifted to the blue wavelength as the concentration of

Hg(II) ions increased, indicating that the oxidation of Ag(0) to Ag(I) was occurred. It appears that

the AgNPs were oxidized by Hg(II), resulting in disintegration of the AgNPs into smaller particles,

which changed their shape and consequently altered their SPR extinction band(s). The calibration

curve of this technique was demonstrated from 5-15 ppm (r2=0.9956), the limit of detection (LOD)

was 4.51 ppm, defined as the Hg concentration corresponding to the mean signal of a zero standard

(n= 10) minus three standard deviations and the precision of measurement (RSD) was lower than

4.75 (n=4). Moreover, the percentage recoveries of spiked drinking water and tap water were 93.39

– 107.80 % and 97.40 – 111.03 %, respectively. The RSD of percentage recoveries in drinking

water and tap water were 4.17 – 6.91 and 4.21 – 9.37, respectively. Interference study reveals that

foreign ions (Ni(II), Pb(II), Mg(II), Cd(II), Zn(II), and Cu(II)) did not affect the measurement since

their redox potential are lower than Ag+/Ag. The developed method has illustrated the possibility

of using AgNPs for colorimetric detection of aqueous Hg (II) with a simple, rapid, and selective

detection.

Keywords Mercury(Hg); Silver Nanoparticles(AgNPs); Colorimetry; Tap water; Drinking water



Application of Dissociation Reaction of Methyl Orange for

Quantitative Analysis of Ethanol by Using Gas - Diffusion Flow

Injection Analysis

Panuwat Chankaw, Nuanlaor Ratanawimarnwong*

Department of Chemistry, Faculty of science, Srinakharinwirot University, Sukhumvit 23 Bangkok 10110,

Thailand


Quantitative analysis of ethanol was investigated based on dissociation reaction of methyl orange

(MO). It was observed that MO‟s dissociation constant was depending on difference ethanol

composition. Under the optimum pH of 3.4, basic form of MO was monitored at 530 nm. Gas

diffusion coupled with flow injection system was adopted in this work to improve selectivity of

ethanol analysis. By means of this system, standard/sample solution containing ethanol was

introduced into the flow system, using time based injection, as a donor stream to the GD unit to

allow diffusion of ethanol through a hydrophobic membrane. Diffused ethanol was then re-

dissolved into a static acceptor solution containing methyl orange in acetate buffer pH 3.4. Under

investigated conditions, a linear calibration of ethanol standards between 5% (v/v) to 40% (v/v)

was obtained (Abs530nm = 0.007 [ethanol, %v/v] +0.012, r2 = 0.999). The proposed MO‟s

dissociation reaction can be used as an alternative method for ethanol determination in alcoholic

beverages instead of using potassium dichromate reaction that considered as toxic chemicals.

Keywords ethanol, methyl orange, gas - diffusion flow injection analysis



Development of Phosphate Assay in Frozen Food Samples

Employing Molybdenum Blue Method

Atittaya Charumram1,2

, Kanokwan kiwfo1,2

, Wasin Wongwilai1,2

, Kate Grudpan1,2*

1Department of Chemistry, Faculty of Science, Chiang Mai University, Thailand 2Center of Excellence for Innovation in Analytical Science and Technology,

Chiang Mai University, Thailand

*E-mail: [email protected]; [email protected]

Phosphate is an additive in frozen food samples. It should be added not more than 5000 mg/kg. To

date, no reported procedure is given. This presentation will report the investigation on the

development of phosphate assay in frozen food samples by employing molybdenum blue method.

Molybdenum blue method was re-investigated for high phosphate concentration determination.

Sample preparation for frozen food samples for the determination of phosphate by the

molybdenum blue method was also investigated. A sample after weighing (1 package, 150 g) is

ground before being put in water (1 L) with constant stirring for 30 min. A clear solution after

filtration is diluted appropriately to suit the calibration graph of phosphate (1-15 µg) which is

constructed by using a single standard solution. A phosphate standard of 50 µg/mL was employed

for the purpose. A series of appropriate volumes of the standard was transferred into a series of

volumetric flasks (25.00 mL) following by addition of 0.8 mL reagent (a mixture of 0.03 mol/L

ammonium molybdate, 2.5 mol/L sulfuric acid, 0.01 mol/L ascorbic acid and 8.2 x 10-3

mol/L

potassium antimonyl tartrate) and before making to the mark of each flask by adding water. The

solution was spectrophotometrically measured at 880 nm. The phosphate content of each sample

can be evaluated via the calibration graph. Phosphate contents in samples of cuttlefish and shrimp

taken from a market were found to be 588 and 1288 mg/kg (wet (pack) weight).

Keywords Phosphate; Molybdenum blue; Frozen food



Amperometric Biosensor for Sulfite Determination in Beverages

Using Glassy Carbon Modified with Hybrid Nano-materials

Electrode in Simple Flow Injection System

Wongduan Sroysee, Maliwan Amatatongchai*

Department of Chemistry and Center of Excellent for Innovation in Chemistry, Faculty of Science, Ubon

Ratchathani University Ubon Ratchathani , 34190, Thailand

*E-mail: [email protected] or [email protected]

A simple flow injection system with amperometric detection on a sulfite biosensor was developed

for sensitive and rapid measurement of sulfite. The biosensor was developed based on the hybrid

materials, composed of carboxylic functionalized carbon nanotubes, poly(diallyldimethyl

ammonium chloride) and gold nanoparticle (CNT-COOH-PDDA-AuNPs) coated on a glassy

carbon (GC) electrode, which constructed an effective immobilization matrix and made the

immobilized components hold high stability and bioactivity. Sulfite oxidase (SOx) was

immobilized to CNT-COOH-PDDA-AuNPs and cytochrome C composite film by using

glutaraldehyde (Glu). Electrochemical oxidation of sulfite was studied at the developed biosensor

(GC/CNT-COOH-PDDA-AuNPs/SOx) in 0.1 M phosphate buffer pH 7.0 using cyclic voltammetry.

The biosensor displayed good electrocatalytic activity towards the oxidation of sulfite. The

apparent Michaelis–Menten constant was determined which has value of 0.49 mM. The developed

biosensor was applied in the flow injection analysis system for amperometric detection of sulfite

using solution of 0.1 M phosphate buffer (pH 7.0) as a carrier and applying a potential of +0.3 V at

the working electrode. The proposed sulfite biosensor exhibits linear calibration over the range of

2-200 mg.L-1

of sulfite with slope of 60 nA.mg-1

.L and correlation coefficient of 0.9952. Potential

use of this method for sulfite determination in beverages and the agreement with the standard

method will be discussed.

Keywords Sulfite, Biosensor; FIA; CNT-COOH; PDDA; AuNPs; Amperometry



Rapid Quantitative Alkali Test for Trinitrotoluene in Soil

Khanittha Malathong1, Worawit Wongniramaikul

2,3, Aree Choodum

1,2*

1Department of Applied Science, Faculty of Science, Prince of Songkla University, Hat Yai,

Songkhla 90112, Thailand 2

Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla

90112 Thailand 3

Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Phuket

83120 Thailand


Trinitrotoluene (TNT) is the most widely deployed high explosive. It is also known to be highly

toxic for macroorganisms and microorganisms when contaminated in soil. The high effective

and rapid detection method was then required for TNT analysis. In this work, a simple and rapid

portable quantitative analysis of TNT in soil was investigated using alkali test. Quantification of

the red-violet product from the test was achieved using application of photography by a smart

phone, iPhone 4.0. The Red Green Blue (RGB) value from digital images were analyzed by

custom-built RGB analysis program and the relationships between the RGB values and the

concentration of TNT was studied. Quantification of TNT in soil was validated by spiking a

know concentration of TNT standards to the soil extracts. This method provided a wide linear

range (0.5 to 100 mg/L) with good inter-day precision (1.07-1.61 %RSD, n= 6) and low

detection limits (0.28 ± 0.01 mg/L). The quantification was achieved within 2 minutes compared

to almost 15 minutes for gas chromatographic method. The developed method shows a good

potential to apply for TNT quantitative analysis in the field.

Keywords Digital images; Red Green Blue color system; iPhone; Trinitrotoluene



Characterization and Chemical Screening of Grey, Orange, and

Pink Colour Pigments from Actinomycetes from Hymenoptera:

Sphecidae Nested-Soil in Kaw Noi Bam Rung Dan Dam,

Phitsanulok Province

Nobparat Laowang1, Naruemon Thaungoon

2, Tanin Tangkuaram

3, Anchana Preechaworapun

1*

1 Program of Chemistry, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok, Thailand 65000 2 Program of Biology, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok, Thailand 65000 3 Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai, Thailand 50290


Actinomycete strains (strain L17, M10 and N1) were isolated from Hymenoptera: Sphecidae

Nested-Soil in Kaw Noi Bam Rung Dan Dam, Phitsanulok Province and found to produce the grey,

orange, and pink colour pigments, respectively. Crude pigments was produced from strain L17,

M10 and N1 by solid state fermentation using broken-milled rice medium followed by extraction

with 50% methanol for strain L17, and 75% methanol for strain M10 and N1 at total yield of 2.25

g/100 g, 6.37 g/100 g and 1.21 g/100 g, respectively. The crude of orange and grey pigments was

stable in temperature range of 25-40 C, oxidant (H2O2, KCrO7, and KMnO4) and reducer (Na2SO3).

The chemical property was characterized using UV-visible spectroscopy, thin-layer

chromatography, and Fourier transforms infrared analysis. The crude pigments were partially

purified using thin layer chromatography with the solvent system dichloromethane:methanol

(75:25), dichloromethane:methanol (95:5) and 100% methanol for strain L17, M10, and N1,

respectively. The Rf value was calculated as 0.58 for strain L17, 0.65 for strain M10, and 0.75 for

stain N1. Based on the results of chemical screening, all of pigments were tentatively identified as

group of steroids, sugar, sterols or triterpeenes, and primary amine. Furthermore, a strain M10 was

received group of anthaquinone.

Keywords Actinomycete strain; Grey pigment; Orange pigment; Pink pigment; Physical and

chemical properties



Detection of Browning Substance in Electrolyte products by

Reverse Phase High Performance Liquid Chromatography

Pornpimol Muangthai*, Yonrawee Wiwatchankit

Analytical Chemistry Research Unit, Department of Chemistry .Faculty of Science,

Srinakharinwirot University, Bangkok , 10110, Thailand

*E-mail: pornpi @swu.ac.th

There are many Electrolytic Products in the market. Some of them were used as electrolyte for cure

symptom of diarrehoea people, some products were used as the energy served for athlete and

labour people.The Electrolytic Products contain sodium ion, potassium ion and also sugar.

Hydroxymethylfurfuraldehyde is the one product that relate the browning substance occurrence in

food, especially in sweeten products such as honey. It was claimed as a toxic substance. The aim of

this work was to detect the browning substance as hydroxymethylfurfuraldehyde content by High

Performance Liquid Chromatography. The optimum condition for analysis hydroxy-

methylfurfuraldehyde was studied and validate method, then the method was applied for analysis

its content in Electrolytic Products. The optimization studied presented that

hydroxymethylfurfuraldehyde could be separated and detected by C18 column, the mixture of

water/acetonitrile (90:10, v/v) was the mobile phase solvent with isocratic elution that controlled

flow rate at 1.5 ml/min. and detected at 280 nm by photodiode array detector (DAD). The limit

of detection (LOD) and limit of quantitation (LOQ) were 0.89 µg/L and 2.9 µg/L, respectively. The

relative standard deviation(%RSD) ( replicate numbers = 10) was 0.55%.The hydroxy-

methylfurfuraldehyde was detected in Electrolytic Products samples within the range of 0.03 - 6

mg/L.This work proved that the toxic substance such as hydroxymethylfurfuraldehyde present in

the Electrolytic Products, so the consumer should care about this substance.

Keywords Browning Substance , Electrolyte Products , Reverse Phase High Performance Liquid

Chromatography, Hydroxymethylfurfuraldehyde



Fe3O4/Au Nanoparticles for Immobilization of Glucose Oxidase

on Screen Printed Carbon Electrode Based on Flow Injection

Analysis for Glucose Determination

Preeyanuch Butmee1, Kurt Kalcher

2, Chalida Pukahuta

3, Anchalee Samphao

1*

1Department of Chemistry, Faculty of Science, Ubon Ratchathani University,

Warin Chamrap, Ubon Ratchathani, 34190 Thailand 2Institute of Chemistry-Analytical Chemistry, Karl-Franzens University, A-8010 Graz, Austria

3Department of Microbiology, Faculty of Science, Ubon Ratchathani University,

Warin Chamrap, Ubon Ratchathani, 34190 Thailand


In this research, glucose oxidase (GOx) chemisorbed on core shell Fe3O4/Au nanoparticles and then

subsequently immobilized by an extra pillar magnet on a screen printed carbon electrode modified

with 5 wt% manganese oxide (GOx/Fe3O4/MnO2/SPCE) as a working electrode (WE) performing

with an amperometry has been studied. The GOx/Fe3O4/MnO2/SPCE based on flow injection

analysis (FIA) has been developed for the determination of glucose in real samples. The flow

injection system consisted of a peristaltic pump as carrier out a solution for the system, a 100 µL

injection volume, an electrochemical cell (with WE, Ag/AgCl as a reference electrode and a

platinum wire as an auxiliary electrode), a potentiostat/galvanostat and readout system was

performed. The optimal results of flow rate at 1.7 mL/min, the applied potential of +0.38 V,

phosphate buffer solution at pH 7.0 as the supporting electrolyte and the enzyme glucose oxidase

loading of 168.4 U/cm2, respectively, were obtained. Furthermore, the GOx/Fe3O4/MnO2/SPCE was

experimentally evaluated with respect to a linear response range from 40-800 mg/L glucose with

sensitivity of 0.0005 µA.L.mg-1

, a detection limit of 12 mg/L and a quantification limit of 40 mg/L.

Moreover, repeatability (n=10) of 3.7 % and reproducibility (n=3) of 2.5 % were also obtained.

Keywords Glucose; Flow injection system; Glucose oxidase; Core shell Fe3O4/Au; Screen printed

carbon electrode



Determination of Ferulic Acid in Corn by High-Performance

Liquid Chromatography (HPLC)

Jaruwan Daengchat*, Pornpimol Muangthai

Analytical Chemistry Research Unit, Department of Chemistry, Faculty of science, Srinakharinwirot

University, Bangkok 10110, Thailand


Corns are a good source of ferulic acid (4-hydroxy-3-methoxycinnamic acid) associated with

reduced risk of chronic diseases. In the present study, the ferulic acid in corns (cob, kernel and

husk) was investigated. This research used high-performance liquid chromatography–diode array

detection (HPLC–DAD) method for determination of ferulic acid in Corn. Extraction of ferulic

acid from corn sample using ultrasonication and centrifugation with organic solvent. The

optimized parameters such as mobile phase type, flow rate, heating effect and extraction time were

studied and detected by ultraviolet detector at 320 nm. Ferulic acid extracts were separated on a

SphereClone C18 column, 5µm (250 mm x 4.6 mm) thermostated at 30 ºC, using a mobile phase

system consisting of 1% (v/v) acetic acid in water (pH 2.6) : methanol (50:50 v/v). The flow rate

was controlled at 1.0 ml/min. The condition for extraction ferulic acid from corn used the heating

time at 100 ºC and extraction time for 20 min. Under investigated conditions, a linear calibration of

ferulic acid standards between 0.2 to 10.0 µg/ml was obtained with r2 as 0.999. It was found that

cob, kernel and husk contained ferulic acid as 35.23, 11.30 and 3.32 µg/g respectively. This work

confirmed that corn contained the ferulic acid.

Keywords ferulic acid, corn, high-performance liquid chromatography



Zinc Oxide Determination in Sunscreen Cream using

Square Wave Anodic Stripping Voltammetry (SWASV)

Rungnapa Pimsen1*, Sudkamol Lasopa

2

1Faculty of Science and Technology, Nakhon Si Thammarat Rajabhat University

Nakhon Si Thammarat, 80280, Thailand 2Faculty of Science and Technology, Sakon Nakhon Rajabhat University

Sakon Nakhon, 47000, Thailand


Zinc oxide (ZnO) is frequently employed in sunscreens as inorganic physical sun blockers. Such

filters attenuate the UV irradiation by scattering and absorption of the radiation. The maximum

concentration of ZnO as defined by the US Food and Drug Administration (FDA) is not more than

25%. Therefore, ZnO in sunscreens cream is necessary to determine because it penetrated into

viable skin cells that can be induced free radical formation and damaged the skin cells. In recent

year, atomic absorption spectroscopy, flame atomic absorption and ICP-AES spectroscopy were

used for ZnO analysis. Many techniques were used for sample preparation such as microwave-

assisted digestion and acid digestion which were costly, toxicant, time-consuming, and

complicated methods. Thus, the proposed methodologies for measuring ZnO are based on a sample

emulsification of sunscreens cream using ethanol and sulfuric acid reaction at various mole ratio;

1:3, 2:2 and 3:1. In this work, the direct determination of ZnO in sunscreens cream was carried out

by square wave anodic stripping voltammetry (SWASV) technique at the glassy carbon electrode

(GCE). The zinc ions were deposited by reduction at -1.8 V on a bare glassy carbon surface, duration time 300 sec, frequency 15 Hz, step potential 0.03 V and amplitude 0.12 V. A good

linearity range (R2 = 0.997) was obtained in the concentration range of 0.2–4.0 mg/L with a limit

of detection (LOD) of 0.015 mg/L of Zn(II). A relative standard deviation of 2.15% (n = 20) was

obtained for 0.2 mg/L of Zn(II) solution. The practical analytical utility of the method was verified

by the determination of Zn(II) in spiked sunscreen cream samples by using 3:1 mole ratio of

ethanol:sulfuric acid, where 89–110% recovery of Zn(II) was achieved.

Keywords Zinc oxide; sunscreen cream; square wave anodic stripping voltammetry



Quantitative and Chromatographic Fingerprint Analyses of

Banana Residues Using High Performance Liquid

Chromatography

Orawan Kritsunankul1,

*, Benjaporn Pramote1, Neti Waranuch

2, Jarupa Viyoch

2,

Kornkanok Ingkaninan3, Anuphan Sittichokechaiwutt

4

1 Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Naresuan University, Phitsanulok 65000, Thailand 2 Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Naresuan University,

Phitsanulok 65000, Thailand 3 Department of Pharmaceutical Chemistry and Phamacognosy, Faculty of Pharmacutical Sciences,

Naresuan University, Phitsanulok 65000, Thailand 4 Department of Preventive Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok 65000,

Thailand


A simple method of liquid-liquid extraction combined with high performance liquid

chromatography (HPLC) was investigated for quantitative analysis of five antioxidant compounds

(gallic acid, gallocatechin, catechin, epicatechin and epigallocatechin gallate) and chromatographic

fingerprint analysis of banana (named Kluai Nam Wa Mali Oung) residue samples with different

parts (peel, comb and bundle), which randomly collected (in winter season) from different

provinces (Phitsanulok, Sukhothai and Kamphaeng Phet). Under optimum conditions of two

methods, linear calibration graphs in the ranges of 0.25-20.0 mg/L for gallic acid and 0.50-30.0

mg/L for gallocatechin, catechin, epicatechin and epigallocatechin gallate were obtained for

quantitative analysis. The percentage recoveries of the studied antioxidants obtained from the

method were found in the range of 70±2 - 128±4, by spiking banana samples with mixed

antioxidant standard concentration at 4.0 and 8.0 mg/L. For fingerprint analysis, ten characteristic

peaks were selected to evaluate the similarities of banana residue samples and HPLC

chromatograms of eighteen samples were showed similar pattern. The proposed combination of the

quantitative and chromatographic fingerprint analyses has been successfully evaluated for the

quantity and quality profiles of antioxidants in banana residue samples.

Keywords Antioxidant compound; High performance liquid chromatography; Banana residue;

Chromatographic fingerprint analysis




Characterization and Chemical Screening of Yellow, and Green

Colour Pigments from Actinomycetes from Hymenoptera:

Sphecidae Nested-Soil in Kaw Noi Bam Rung Dan Dam,

Phitsanulok Province

Tik Ouiram1, Naruemon Thaungoon

2, Tanin Tangkuaram


1*


Phitsanulok, Thailand 65000 2 Program of Biology, Faculty of Science and Technology, Pibulsongkram Rajabhat University, Phitsanulok,

Thailand 65000 3 Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai, Thailand 50290


Actinomycete strain (strain K10 and O19) was isolated from Hymenoptera: Sphecidae Nested-Soil

in Kaw Noi Bam Rung Dan Dam, Phitsanulok Province and found to produce a yellow and green

colour pigments, respectively. Crude pigments was produced from strain K10 and O19 by solid

state fermentation using broken-milled rice medium followed by extraction with 50% methanol at a

total yield of 1.60 g/100 g and 1.02 g/100 g, respectively. The both crude pigments were well

soluble in 50% methanol, and stable in temperature range of 25-80 C, oxidant (H2O2) and reducer

(Na2SO3). The chemical property was characterized using UV-visible spectroscopy, thin-layer

chromatography, and Fourier transforms infrared analysis. The crude pigments were partially

purified using thin layer chromatography with the solvent system dichloromethane:methanol (95:5)

and the Rf value was calculated as 0.625 for crude of green pigment and 0.58, 0.68, 0.72, and 0.75

for crude of yellow pigment. Based on the results of chemical screening, the pigment was

tentatively identified as group of steroids, sugar, sterols or triterpeenes, and anthaquinones for crude

of green pigment and group of primary amine, steroids, sugar, sterols or triterpenes, and flavonoids

for crude of yellow pigment.

Keywords Actinomycete strain; Yellow pigment; Green pigment; Physical and chemical properties



A Simple and Sensitive Spectrophotometric Method for

Determination of Sn(IV) after Preconcentration With

Dispersive Liquid-Liquid Microextraction

Naphatra Saemram, Supalax Srijaranai*

Materials Chemistry Research Unit, Department of Chemistry, Faculty of Science, Khon Kaen University,

Khon Kaen 40002, Thailand


A simple spectrophotometric method for determination of Sn(IV) was demonstrated. The method

is based on the complexation of Sn(IV) with pyrocatechol violet (PCV) in micellar media before

subjecting to dispersive liquid-liquid microextraction (DLLME). In DLLME, the Sn(IV)-PCV

complex was then concentrated using 1-dodecanol as the extraction solvent. The experimental

parameters affecting complexation and DLLME were investigated and optimized. The optimum

conditions were as followed: 0.06mM PCV, 0.2mM CTAB, glycine buffer pH 3 for complexation,

while 400 µL dodecanol, 1% (w/v) NaCl, and centrifuged at 3,500 rpm for 15 min for DLLME.

DLLME could increase sensitivity of 1.4 times compared to the detection of Sn(IV)-PCV complex.

The interferences of anions and cations were studied. The application of the proposed method for

the determination of Sn(IV) in soft drinks (canned juices) and water samples is in progress.

Keywords Tin; Pyrocatechol violet; Spectrophotometry ; DLLME



A Continuous Flow Photo-reactor Equipped with On-line

Monitoring System for Investigation of Photocatalyst Efficiency

on Nitrogen Dioxide Removal

Korbua Chaisiwamongkhol*,1,2

Siwaporn Mejoo Smith,1 Chatvalee Kalambaheti,

3 and Kanchana Uraisin*

1,2

1Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs.)


Mahidol University, Rama VI Rd, Bangkok 10400, Thailand. 3PTT Research & Technology Institute, Phaholyothin Rd. Ayutthaya Province 13170, Thailand.


In this work, the on-line monitoring system equipped with the continuous flow reactor was

proposed. This system was utilized for investigation of the photocatalyst efficiency on nitrogen

dioxide (NO2) removal. The system consists of two parts which are gas flow through system with

quartz tubing reactor (length 15 cm, i.d. 2 cm) and on-line monitoring of the residual NO2 by flow

injection (FI) system. A preliminary result was achieved by using commercial titanium dioxide-

based photocatalyst named „P25‟ as a model for testing the catalyst treatment efficiency on NO2

degradation. The coated TiO2 photocatalyst on glass beads was packed inside quartz reactor where

standard NO2 (50 ppmv) was continuously flowed. Decomposition of NO2 was performed inside

the reactor when NO2 reacted with P25 under UV radiation (108 watts). The residual NO2 from the

reactor was measured by using FI system. Motoring of the residual NO2 was carried out by

trapping NO2 gas into triethanolamine (TEA) solution via gas diffusion (GD) unit where NO2 gas

was converted into nitrite (NO2-). The trapped zone was further reacted with Griess reagent to form

the pink color of azo-compound which can be spectrophotometrically monitored at 540 nm. The

photocatalyst efficiency was reported in term of percentage removal of nitrogen dioxide. The

continuous flow reactor with on-line monitoring of residual NO2 was attained.

Keywords Nitrogen dioxide removal; Flow injection analysis; Titanium dioxide; Griess reagent



Rapid Semi-quantitative Analysis of Ammonium Nitrate using

Digital Image-based Colorimetry

Pichapat Boonsamran1, Worawit Wongniramaikul

2, 3, Aree Choodum

1, 2*

1Department of Applied Science, Faculty of Science, Prince of Songkla University, Hat Yai Songkhla

90112, Thailand 2Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112

Thailand 3Faculty of Technology and Environment, Prince of Songkla University, Phuket Campus, Phuket

83120 Thailand *E-mail: [email protected], [email protected]

Ammonium nitrate (AN) is an inorganic compound which could be combined with fuel oil to

produce a high explosive named “ANFO”. Digital image-based colorimetry was used for

quantitative analysis of ammonium nitrate. The colorimetric test was based on the reduction of

ammonium nitrate by zinc powder before reacted with sulfanilamide and N-(1-naphthyl) ethylene

diamine to be violet azo dye. The colored product from the selective test was quantified using an

innovative application of photography, and the Red Green Blue (RGB) value was analyzed by the

custom-built RGB analysis program. The relationships between the RGB values and the

concentrations of ammonium nitrate were studied. The linear range of the green intensity was

0.005-0.5 mg/mL with good linearity (R2>0.99). The sensitivity was found to be 0.150 ± 0.002

AU/ (mg/mL). The method can be used both qualitative and quantitative analysis which would be

benefit for a rapid detection of ammonium nitrate in ANFO explosive and soil samples both in

laboratory and outdoor.

Keywords: Digital images; Red Green Blue color system; Colorimetry; Ammonium Nitrate



The Treatment of Cotton Fabric for Dyeing with Natural Dye

Sudkamon Lasopha 1*, Orasa Choola-aied

2, Rungnapa Pimsan

3

1Department of Chemistry, Faculty of Science and Technology, SaKhonNaKhonRajabhat University

SaKhonNaKhon 47000, Thailand 2King Mongkut's Institute of Technology Ladkrabang,Chumphon Campus,Pathio, Chumphon 86160, Thailand 3Department of Chemistry, Faculty of Science and Technology, Nakhon Si Thammarat Rajabhat University

Nakhon Si Thammarat 80280, Thailand


The most traditional dyeing process, the natural dye are used instead of synthetic dyes. However,

natural dyes have inadequate fastness properties and technical problems. In this study, coconut coir

fiber was used as natural dye for conventional mordanting were compared with that of chitosan and

zinc oxide treatment on the dyeing on cotton fabric. The progress of dyeing was monitored at max

281.5 nm using uv-visible spectroscopy. Results revealed that under the same dyeing condition of a

material to liquor ratio 1:100, 90 minutes at 80C. All mordants namely alum, copper sulphate,

ferrous sulphate, soybean extract, young tamarind leaf extract and wood ash solution were found to

be suitable for application on cotton fabric by conventional premordanting methods. In addition,

chitosan and zinc oxide pretreatment that the optimum condition of 20, 60 minutes at 160C to cure

and 0.2, 5% w/v of chitosan and zinc oxide, respectively resulted in an increase in dye uptake with

the corresponding untreated sample. However, the dyeing after treatment with chitosan and zinc

oxide exercised its superiority in dye uptake compared with conventional mordanting in all case.

Keywords: chitosan, zinc oxide, mordant, cotton fabric

http://www.kmitl.ac.th/



Study for Spectrophotometric Determination of Copper(II) and

Cerium(III) with N,N-bis(5-methoxy-2-hydroxybenzyl)

methylamine

Watcharapol Sienglum1, Pornpun Pornsinlapatip

1*, Nattamon Koonsang

1, Apirat Laobuthee

2

1Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand

2Department of Materials Engineering, Faculty of Engineering, Kasetsart University, Bangkok, 10900,

Thailand


Spectrophotometric methods were studied and developed for the determination of Cu(II) and

Ce(III) using N,N-bis(5-methoxy-2-hydroxybenzyl)methylamine (MeMD), a derivative of

benzoxazine dimers. The methods were based upon the formation of coloured complex of metal

with MeMD in 99.9% ethanolic medium. The two metal-MeMD complexes were studied

separately by means of visible absorptiometry. The yellow-coloured Cu(II)-MeMD exhibited the

maximum absorption at the wavelength of 428.0 nm, whilst the absorption peak of the brown

Ce(III)-MeMD complex was found at 468.0 nm. Under the studied conditions, the composition of

Cu(II)-MeMD complex determined by the continuous variation (Job‟s plot) and the molar ratio

methods was found to be 1:3 of Cu(II)-to-MeMD ratio. The composition of Ce(III)-MeMD found in

this study is in agreement with a finding reported previously, that is a ratio of 1:6. The Cu(II)-

MeMD complex was found to be instantly formed and complete after the reagent mixing and was

stable for at least 24 hours. The complexation of Ce(III) with MeMD was slower than that of

Cu(II)-MeMD. However, the maximum absorbance was obtained after 60-minute standing and was

stable for at least 10 hours. The calibration graph for the determination of Cu(II)-MeMD complex

was found to be linear over the range of 3.1-28.5 ppm Cu(II) with R2 = 0.9993. As for the Ce(III)-

MeMD, a linear calibration graph with R2 = 0.9992 was obtained over the range of 2.8-18.2 ppm

Ce(III).

Keywords Cu(II); Ce(III); benzoxazine dimers; MeMD; spectrophotometry.



An Amperometric Glucose Biosensor Based on

The Immobilization of Glucose Oxidase on Gold Electrode

Modified with Carbon Nanotubes-Chitosan Scaffold

and Nickel Ferrite

Wanwisa Moonla1, Anchana Preechaworapun

2, Tanin Tangkuaram

1,3*


2 Department of Chemistry, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok 65000, Thailand 3 Nanoscience and Nanotechnology Research Laboratory, Faculty of Science, Maejo University, Chiang Mai

50290, Thailand


An amperometric biosensor for the quantitative measurement of glucose based on a gold electrode

modified with carbon nanotubes–chitosan scaffold (CNTs-CHIT), nickel ferrite (NiFe2O4) and

glucose oxidase (GOx) (CNTs-CHIT-NiFe2O4/GOx) was developed. The effects of pH value,

applied potential, enzyme loading, CNTs-CHIT-NiFe2O4 content, electroactive interference and the

stability of the optimal biosensor were studied. This biosensor exhibited good analytical

performances in terms of excellent electrocatalytic activities towards the oxidation of H2O2 of

nickel ferrite resulting in the improvement of the detection limit and the increase of the maximum

response current and sensitivity. Calibration curve were investigated under optimum conditions

with an operating potential of -0.2 V versus Ag/AgCl (3 M KCl) electrode. This biosensor had been

applied to determine glucose in blood samples.

Keywords Glucose biosensor; Nickel ferrite; Glucose oxidase; Chitosan scaffold



Determination of Five Flavonoids by Reverse-Phase High-

Performance Liquid Chromatography with Amperometric

Detection at Pencil Carbon Electrode

Chanakorn keawpanom1, Anchana Preechaworapun

1*, Tanin Tangkuaram

2


Phitsanulok, 65000, Thailand 2Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai, 50290, Thailand


Determination of five flavonoids ((+)-catechin, rutin, morin, quercetin, and keampferol) by high-

performance liquid chromatography with amperometric detection was developed. The separation

was performed on monolithic C18 column. The mobile phase consisted of 0.1 mM EDTA in

phosphoric acid (pH 2.3) and methanol (58:42 v/v), and the flow rate was set at 2.0 mL/min.

Amperometric potential of 0.8 V was used. The working electrode, reference electrode, and counter

electrode were a pencil carbon, Ag/AgCl, and stainless steel, respectively. Under the optimum

conditions, all analytes could analyzed in 12 min. The linear ranges were received 1-1000 ppm for

catechin, rutin, and morin, and 0.1-1000 ppm for quercetin and keampferol. Limit of detection was

0.1-1 ppm. The proposed method provided an excellent sensitivity and selectivity, and could be

applied for simultaneous determination of these electroactive phenolic compounds present in

Moringa leaf sample.

Keywords Flavonoids; Moringa leaf; Pencil carbon electrode; HPLC-electrochemical detection



Amperometric Flow Injection Analysis for Hydrogen Peroxide

Determination at Gold Nanoparticle Modified Glassy Carbon

Electrode

Nootjarin Inngam1, Tanin Tangkuaram


1*


Phitsanulok, 65000, Thailand 2 Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai, 50290, Thailand


The electrocatalytic activity of gold nanoparticles electrodeposited on glassy carbon (AuNPs/GC)

electrode was investigated with respect to the oxidation of hydrogen peroxide (H2O2). The

electrodeposited gold nanoparticles on the GC electrode were characterized and confirmed by

scanning electron microscopy (SEM) and their electrochemical catalyzes were subsequently

investigated by amperometric detection. The flow-through working electrode was exhibited with

high sensitivity and reproducibility for the electrochemical oxidation of H2O2. The AuNPs/GC electrode was provided with a long linear dependence on H2O2 concentration in the range of 0.001

mM (LOD) to 35 mM (0.05 M phosphate buffer, pH 7) with high sensitivity of 0.649 A mM-1

.

Keywords Hydrogen peroxide; Gold nanoparticles; Flow injection analysis



Versatility of Capacitively Coupled Contactless Conductivity

Detector for Monitoring Quality of Natural Water

Sumonmarn Chan-Eam1,2

*, Prawpan Inpota1, 3

, Suttipong Saisarai1, 3

, Kittiwut Khamtau1,3

,

Nuanlaor Ratanawimarnwong1, 4

, Kanchana Uraisin1, 3

and Duangjai Nacapricha1, 3

1Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs.)

2Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom, 73000, Thailand

3Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand 4Department of Chemistry, Faculty of Science, Srinakharinwirot University,

Sukhumvit 23 Road, Bangkok 10110, Thailand


The detection principle of a capacitively coupled contactless conductivity detector (C4D) is based

on recognition of current signal of the device that is correlated to the change in conductivity of an

electrolyte solution passing through the C4D cell. Some of the advantages of C4D are simple

construction of detection cell and being corrosion-free for the electrodes. Here, C4D cells were

constructed using two designs including „single-channel C4D‟ and „dual-channel C4D‟. Firstly,

the conventional single-channel C4D was fabricated and attached to a sequential injection (SI)

system for ship-board monitoring of salinity. A peak signal in relation to the change in

conductivity was observed when a zone of saline water travelled through the C4D. The SI system

equipped with the single-channel C4D provided rapid throughput of 60 samples h-1

for the analysis

of salinity. The C4D cell was further developed to a dual-channel C4D. This dual-channel C4D

was incorporated into a flow injection (FI) system as detector. The system was also furnished with

a dialysis unit and two gas diffusion units. It has been demonstrated that the dual-channel C4D can

be used to detect three analytical zones including salinity, carbonate and ammonia simultaneously.

The salinity was analyzed by passing the dialyzed zone of marine water through one of the channel

of the C4D. Carbonate and ammonia were analyzed by converting these species respectively to

CO2 and NH3 gases in the flow system. These gases diffused through the porous hydrophobic

membranes, fitted inside the gas diffusion units, and dissolved in water acceptor streams leading to

conductivity changes comparing to the baseline. These analytical zones of dissolved CO2 and NH3

were transferred to the channels in the dual-channel C4D cell for detection individually. The flow

system gave satisfactorily good limits of quantitation for salinity, carbonate and ammonia at 0.24

‰, 0.31 mmol L-1

, 1.85 µmol L-1

, respectively. Throughput of 20 samples h-1

for simultaneous

analysis could be achieved with RSD of less than 4 %. The system was successfully applied to

natural water samples with results in agreement with those obtained using comparison methods.

Keywords: capacitively coupled contactless conductivity detector (C4D), dialysis, gas diffusion,

salinity, carbonate, ammonia

http://water.epa.gov/type/watersheds/monitoring/index.cfm



Determination of Organic Acid in Varieties Colour Vegetables

by High-Performance Liquid Chromatography

Piyatip Nookaew, Pornpimol Muangthai*

Department of Chemistry, Faculty of science, Srinakharinwirot University, Sukhumvit 23 Bangkok 10110,

Thailand


A high-performance liquid chromatographic (HPLC) separation and quantitation has been

developed for the simultaneous determination of organic acids (tartaric acid and ascorbic acid) in

variety colour vegetables.The chromatographic analysis of organic acids was carried out after their

elution with sulphuric acid solution (0.001 M):methanol (98:2) from C18 stationary phase. Target

compounds were detected by diode array detector at 210 nm. Two organic acid acids were eluted

in 7 minutes. The validation parameters showed efficiency for limits of detection (LOD) and

quantification (LOQ) as 1.01 ± 1.32 and 11.03 ± 1.49 mg/L, respectively. The percentage recovery

was 85 % ± 3.01 The method was applied to analyse those two organic acids in variety colour

vegetables such as purple cauliflower, carrot , yardlong bean , green oak and red oak. The amount

of tartaric acid and ascorbic acid could be detected in all vegetables in the range of 15.6-79.3

mg/100g and 5-9 mg/100g , respectively. It was noticed that all fresh vegetables contained

tartaric acid content higher than ascorbic acid content.

Keyword organic acid, tartaric acid, ascobic acid, colour vegetables



Determination of Lead in Traditional Herbs Recipe by

Flame Atomic Absorption Spectrometry

Wisan Chananchana, Sirirat Phaisansuthichol*

1Program in Chemistry, Faculty of Science, Maejo University, Chiang Mai, 50290 Thailand


A simple method for trace determination of lead in traditional herbs recipe was determined by

flame atomic absorption spectrometry (FAAS). Samples were determined by FAAS after

microwave and wet digestion methods. The result show that the wet digestion procedure provided

better than microwave digestion procedures. The limit of detection (LOD) obtained under the

optimal conditions was 1.0 mg L-1

. The precision of 12 replicate determinations at 15 mg L-1

lead

was 2.00 %RSD. The recovery of spike (30 mg L-1

) added to the samples was estimated within

101-104% range. The investigated metal was found in traditional herbs recipe in concentration

ranging from 20-25 mg L-1

. This method was successfully applied for the determination of lead in

traditional herbs recipe.

Keywords Tradition herbs recipe; AAS; Lead



Determination of Salicylic Acid Content in Pharmaceuticals

using Square-Wave Voltammetric Method

Juthamas Buntungtang1,2

, Jintana Ditkulchaimongkol1, Sasithorn Muncharoen

1,2 *

1Department of Chemistry, Faculty of Science, Burapha University, Chonburi, 20131, Thailand


Burapha University, Chonburi, 20131, Thailand


This research presented the determination of salicylic acid using by square-wave voltammetric

method on a simple pencil-lead electrode. The pencil-lead electrode (Pentel HB Lead, 0.7 mm) used

as working electrode was fabricated in our laboratory. The linearity range of detection was 2.0 to

20.0 mM with detection limit being 1.3 mM. In addition, the electrode was adopted to study the

precision. It was observed that the percentages of relative standard deviation (%RSD) as the method

accuracy for intraday and interday were 3.4% (n=7) and 7.6% (n=5), respectively. Moreover, the

proposed method has been satisfactorily applied for analysis of salicylic content in pharmaceuticals.

Keywords Salicylic acid; Square-wave voltammetry; pharmaceutical product; pencil lead electrode



A Simple Thionine Modified Screen-Printed Carbon Electrode

for Determination of Hydrogen Peroxide

Preeyaporn Reanpang1, 2

, Orawan Chailapakul3, Jaroon Jakmunee

1, 2, 4*

1Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand

2Research Laboratory for Analytical Instrument and Electrochemistry Innovation, Faculty of Science,

Chiang Mai University, Chiang Mai 50200, Thailand 3Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

4Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai

50200, Thailand


The home-made screen-printed carbon electrode (SPCE) modified with thionine (TH) was

proposed for determination of hydrogen peroxide (H2O2). The SPCEs were fabricated by a simple

screen printing method which is widely used for the mass-production of disposable electrochemical

sensor. The conditions used for fabrication of SPCEs were studied including curing time, curing

temperature, dilution ratio and number of repeated printing of carbon ink. Moreover, an

electrochemical surface pretreatment was investigated regarding to their influence on the

electrochemical properties of SPCEs, as studied by cyclic voltammetry. In order to enhance

sensitivity of the electrode, the modification of thionine on SPCEs was carried out with

electropolymerization. The resulting thionine modified SPCEs was successfully applied for

determination of hydrogen peroxide. Recoveries were obtained in the range of 97–107%.

Keywords Screen-printed carbon electrode; Thionine; Hydrogen peroxide



Flow Injection Amperometric Determination of Quinone Based

on a Simple Screen Printed Carbon Electrode

Jantima Upan1, 2

, Preeyaporn Reanpang1, 2

, Orawan Chailapakul3, Jaroon Jakmunee

1, 2, 4*


2Research Laboratory for Analytical Instrument and Electrochemistry Innovation, Faculty of Science,Chiang

Mai University, Chiang Mai 50200, Thailand

3Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand

4Center of Excellence for Innovation in Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai

50200, Thailand


The simple screen printed carbon electrode (SPCE) was created for the determination of quinone

by flow injection amperometric (FI-Amp) system. Quinone was produced from reduction of

hydroquinone which is found in Thai herb and it had skin whitening property. In preliminary study,

cyclic voltammetry of quinone was carried out by using glassy carbon electrode, Ag/AgCl and

platinum as working, reference and auxiliary electrodes, respectively, in 0.1 M citrate buffer

solution pH 5.0. Reduction peak potential of quinone was found at -0.03 V versus Ag/AgCl and

this potential was used in FI-Amp system for further study. In FI-Amp system, some parameters

were optimized including the buffer flow rate, sample volume, reaction coil length and the

operating potential. The results will be discussed. Furthermore, SPCE was also modified with

carbon nanotube (CNT) in order to improve sensitivity of the electrode. As the result, the response

signal of SPCE/CNT is higher than that of SPCE. The reproducibility (n=7) and repeatability

(n=25) of SPCE/CNT were obtained at 4.88% and 2.40 %RSD, respectively. The performance of

SPCE/CNT for determination of quinone has been studied.

Keywords Screen printed carbon electrode; Quinone; Carbon nanotube; Flow injection

amperometry



Flavour of Fresh and Frozen Annona Fruit Pulp Analysis by

GC-FID and GC-MS.

Amlika Rungrod, Supaporn Sangsrichan*

Department of Chemistry, Faculty of Science, Maejo University, San-Sai, Chiang Mai, 5029, Thailand


Custard apple (Annona spp.) is a fruit that aroma contains various aroma components. The research

were described the characterization of the volatile compounds of fresh and frozen Annona fruit

pulp flavor collected in the North of Thailand. Volatile compounds of ripe Annona fruit pulp

extracted with dichloromethane and n-pentane (1:1) and solid phase micro-extraction (SPME) were

analysed by GC-FID and GC-MS. The predominant volatile compounds of Annona flavors are

terpenes, esters, terpenoids, sesquiterpenes and alocohols.

Keywords Annona; Flavour; Frozen; GC-FID; GC-MS; SPME



Lab-on-paper with Electrochemical Detection for Simultaneous

Determination of Lead and Cadmium

Sudkate Chaiyo1, Weena Siangproh


1,3,4**

1Department of Chemistry, Faculty of Science, Chulalongkorn University, 254 Phayathai Road,

Patumwan, Bangkok 10330, Thailand 2Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana,

Bangkok 10110, Thailand 3Center of Excellence on Petrochemical and Advanced Materials Technology, Chulalongkorn University,

254 Phayathai Road, Patumwan, Bangkok, 10330, Thailand 4Electrochemistry and Optical Spectroscopy Research Unit, Department of Chemistry, Faculty of Science,

Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand


**E-mail: [email protected]

The present work describes the application of simple, low cost and highly sensitive paper-based

analytical devices (PADs) with anodic stripping voltammetric detection for the determination of

lead and cadmium. The PADs consists of three electrodes including bismuth modified screen-

printed carbon electrode (SPCE) as working electrode and carbon as reference and counter

electrodes. Three electrodes are initially screen-printed on a filter paper, and 50 μL of Bi(III) was

dropped on the surface of working electrode. This system was to detect lead and cadmium using

anodic stripping voltammetry. Conditions for analysis: supporting electrolyte 0.1 M NaCl pH 4.5,

sample volume 100 μL, concentration of Bi(III) solution 10 mg L-1

, accumulation potential −1.4 V

and accumulation time 120 s. Under this condition, the voltammograms show the relative anodic

stripping current of 15-fold and 10-fold for lead and cadmium, respectively, compared to the bare

SPCE. According to cost versus performance, the utilization of PADs with bismuth modified

SPCE is an alternative choice for low-cost and disposable point-of-care applications.

Keywords Lab-on-paper; Anodic stripping voltammetry; Bismuth; Lead and Cadmium



Simple Derivatization with Subsequent Spectrophotometric

Determination of GABA

Pronrawee Tanpramoon1,2*

, Nathawut Choengchan1,2

1Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs),

2Applied Analytical Chemistry Research Unit, Department of Chemistry, Faculty of Science,

King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520 Thailand


In this work, a simple method for derivatization with subsequent spectrophotometric determination

of -aminobutyric acid (GABA) is presented. GABA was derivatized with 2-hydroxy-1-

naphthaldehyde (3 % w/v) in the presence of borate buffer (pH 8.0) and pure acetonitrile. The

solution was left over night at ambient temperature. Maximum absorption wavelength of the

derivatives was located at 225 nm. Linear calibration was observed in the concentration range from

1 to 40 mg GABA l-1

with good linearity (Abs225 = 7.25 x10-3

[GABA] + 4.19 x10-3

, r2 > 0.99). The

proposed method was applied to GABA-supplemented tablets. Results were agreed very well to the

label concentration. Recoveries were found from 95.1 to 98.9 %. Relative standard deviation was

lower than 2 % when 40 mg GABA l-1

was studied. This implies that the method provided high

accuracy and high precision. However, the method is now applied to green tea and germinated

brown rice samples and is under validated against high performance liquid chromatography using

C-18 column.

Keywords Gamma-aminobutyric acid; Derivatization; Spectrophotometry



Electrochemical Investigation of Salbutamol using

Graphene/polyaniline-modified Screen-printed Carbon

Electrode

Suphunnee Khajornkavinkul1, Narong Praphiraksit

1, Nadnudda Rodthongkum

2 and Orawon Chailapakul

1,3*


Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand 2Mettallurgy and Materials Science Research Institute, Chulalongkorn University, Patumwan, Bangkok

10330, Thailand 3Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Patumwan,



Graphene/polyaniline (G/PANI) nanocomposite-modified screen-printed carbon electrode for the

electrochemical determination of salbutamol has been developed. Recently, G became an attractive

material in electrochemistry due to its high electrical conductivity and electron transfer rate. The

nanocomposite-modified screen-printed carbon electrode was created by electrospraying technique

to generate the homogeneous droplets by applying the high electrical field to liquid droplet. The aim

of this work is: to improve the electrochemical behavior of salbutamol on G/PANI nanocomposite-

modified screen-printed carbon electrode. Characterization of G/PANI nanocomposite-modified

electrode was studied by scanning electron microscope (SEM) and cyclic voltammetry (CV) of

ferri/ferrocyanide. The well-defined cyclic voltammogram of salbutamol was accomplished at

G/PANI modified electrode about 4-fold increase in the current signal compared to an unmodified

electrode. Cyclic voltammetry of salbutamol was obtained in 0.05 M phosphate buffer pH 7 at scan

rate 100 mV/s and the potential in the range 0-1.0 mV. Therefore, G/PANI nanocomposite-modified

screen-printed carbon electrode has been used for the determination of salbutamol in beef or pork

samples. Generally, this proposed method is very simple and inexpensive. All details will be

presented and discussed.

Keywords graphene; polyaniline; salbutamol; electrochemical detection



Chemical Screening of Violet Colour Pigment from

Actinomycetes from Hymenoptera: Sphecidae Nested-Soil in

Kaw Noi Bam Rung Dan Dam, Phitsanulok Province and

Applied for Acid-base Indicator

Tik Ouiram1, Naruemon Thaungoon

2, Tanin Tangkuaram


1*


Phitsanulok, Thailand 65000 2 Program of Biology, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok, Thailand 65000 3 Department of Chemistry, Faculty of Science, Maejo University, Chiang Mai, Thailand 50290


Actinomycete strain (strain O20) was isolated from Hymenoptera: Sphecidae Nested-Soil in Kaw

Noi Bam Rung Dan Dam, Phitsanulok Province and found to produce a violet colour pigment.

Crude pigments was produced from strain O20 by solid state fermentation using broken-milled rice

medium followed by extraction with dichloromethane at a total yield of 0.63 g/100 g. The crude

pigment was well soluble in dichloromethane. The chemical property was characterized using UV-

visible spectroscopy, thin-layer chromatography, and Fourier transforms infrared analysis. The

crude pigment was partially purified using thin layer chromatography with the solvent system

dichloromethane:methanol (95:5) and the Rf value was calculated as 0.92. The result of chemical

screening, the pigment was tentatively identified as group of primary amine, steroids, sugar, sterols

or triterpeenes, and anthaquinones. Crude pigment was applied to paper indicator for acid-base

analysis.

Keywords Actinomycete strain; Violet pigment; Physical and chemical properties; Acid-base

indicator



Sequential Injection Chromatography for Separation of

Phenolic Compounds in Wood Vinegar with Automatic Sample

Dilution and Fraction Collection

Arjnarong Mathaweesansurn

1, 2 *, Suwannee Janyapoon

2, Duangjai Nacapricha

1,3, Nathawut Choengchan

1, 2

1 Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs),

2 Applied Analytical Chemistry Research Unit, Department of Chemistry, Faculty of Science,

King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520 Thailand 3Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Mahidol University, Bangkok 10400, Thailand.


In this work, sequential injection chromatography (SIC) was presented for separation of phenolic

compounds, namely gallic acid, vanillic acid and syringol in wood vinegar. The SIC system was

comprised of a monolithic column (Chromolith flash RP-18eTM

) coupled to an Auto-pretTM

module. The module was composed of a syringe pump and two multi-selection valves. One valve

was placed between the pump and the column and was used for sample dilution. Another valve

was inserted next to a spectrophotometer and was exploited for fraction collection of the isolated

phenolic compound. The fractions will be purified for further usage as cosmetic and food additives

in the next work.

Optimal separation conditions for the SIC are listed as the followings: injected volume; 20 μL,

mobile phase; methanol (10 %) in acetate buffer (pH 3.0), flow rate; 2.0 ml min-1

and detection

wavelength; 264 nm. Retention times were highly precise (RSD = 1.14 to 2.70 %). Linear

calibrations were ranged from 0.1 to 200 mg l-1

with good linearity (r2 > 0.99) for all three phenolic

compounds. Recoveries were observed from 97 to 114 %. Analytical procedures, including

sample dilution, separation and fraction collection were complete within 7 min. The system was

applied to wood vinegar samples, from Eucalyptus tree. Each collected fraction was identified by

comparison of its absorption spectrum to the spectrum of standard solution. Similar spectral

absorption pattern was observed for each phenolic substance.

The SIC system was validated to high performance liquid chromatography (HPLC) under the same

separation conditions. By the statistical paired t-test, the contents of the phenolic compounds were

not significant different. Advantages of the proposed SIC against the HPLC are that automatic

sample dilution and fraction collection can be achieved.

Keywords Sequential injection chromatography; Wood vinegar; Gallic acid; Vanillic acid;

Syringol; Automatic sample dilution; Automatic fraction collection.



Simple Spectrophotometric Method for Determination of

Iodine Value of Vegetable Oils

Thidarat Kruatian1,2

, Kritsana Jitmanee1, 2, 3, 4*


2Research Laboratory for Analytical Instrument and Electrochemistry Innovation, Faculty of Science,

Chiang Mai University, Chiang Mai 50200, Thailand 3Center of Excellence for Innovation in Analytical Science and Technology, Chiang Mai University,

Chiang Mai 50200, Thailand 4Science and Technology Research Institute, Chiang Mai University, Chiang Mai 50200, Thailand


A simple spectrophotometric detection of remaining Hanus solution for the determination of iodine

value of vegetable oils has been proposed. Hanus solution after reacting with vegetable oil was

mixed with potassium iodide solution producing triiodide ions. The amount of triiodide ions could

be determined spectrophotometrically at 350 nm. The calibration graph was constructed by plotting

the absorbance at 350 nm versus the molar concentration of Hanus solution. Under the optimal

conditions a linear calibration graph ranged from 0.02 to 0.10 mol/L of Hanus solution with r2 of

0.999. The method was applied to commercial vegetable oils and the iodine values of vegetable

oils were observed in range of 8-125. The results obtained by the proposed method agreed well

with those obtained by the reference method. The analytical procedures were simple, required short

analysis time, and used small amount of solvent and reagent.

Keywords Spectrophotometry; Iodine value; Vegetable oils



Cross Injection Analysis: Concept and Its Applications

Thitirat Mantim1,2

, Patidta Satranurak1,2

, Nathawut Choengchan1,3

, Kanchana Uraisin1,2

, Prapin Wilairat1,4

and Duangjai Nacapricha1,2,

*

1 Flow Innovation Research for Science and Technology Laboratories (First labs),

2 Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science,

Mahidol University, Rama 6 Road, Bangkok, Thailand, 10400, 3 Department of Chemistry, Faculty of Science, King Mongkut’s Institute of Technology Ladkrabang,

Bangkok 10520, Thailand. 4 National Doping Control Centre, Mahidol University, Bangkok 10400, Thailand.


Recently, a new concept for simultaneous injection of sample and reagents in flow analysis called

„cross injection analysis (CIA) was presented by D. Nacapricha et al. [1]. In CIA, a rectangular

acrylic block (5 3 1.5 cm), with crossing cylindrical channels drilled out along x- and y- axis of

the block, called „CIA platform‟ was designed and employed for simultaneous introduction of

sample and reagents. The x-axis channel is the main analytical flow path used for liquid carrier.

The sample and reagents are introduced into the analytical flow path (x-channel) via individual

pump tube connected to the y-channels of the platform. A cross-flow mode is used for

simultaneous introduction of sample, reagents and carrier to improve the mixing of sample and

reagents. After introduction step, the reaction zone in the x-channel was flushed to the detector

using through the x-channel. The flows in x- and y-channels are driven by computer controlled

peristaltic pumps. The applications of CIA will be presented for (i) determination of Fe(II) in

multivitamin tablets using spectrophotrometric detection of Fe(II)-1,10-phenanthroline complexes

and the speciation of Fe(II) and Fe(III); and (ii) dual-measurement of Fe(III) and creatinine in urine

samples of thalassemic patients undergoing treatment with deferiprone (iron chelator drug).

Keywords Cross Injection Analysis; Concept of CIA; Application of CIA; Fe(II); Fe(III);

Creatinine



Quantitative Flow Analysis of Sulfide in Water Samples with

On-line Membraneless Vaporization of Hydrogen Sulfide and

C4D detector

Nattapong Chantipmanee1,2

, Waleed Al-Ahmad,1,2

Thitirat Mantim,1,2 Nuanlaor Ratanawimarnwong,

1,3

Duangjai Nacapricha,1,2

*

1Flow Innovation-Research for Science and Technology Laboratories (FIRST labs)

2 Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Mahidol University, Bangkok 10400, Thailand

3Department of Chemistry, Faculty of Science, Srinakharinwirot University,


E-mail: [email protected]

The new design of a „membraneless vaporization (MBL-VP) apparatus‟ [1], was used in a flow

system for direct determination of sulfide. The MBL-VP apparatus was used as on-line device to

separate hydrogen sulfide gas from the sample fluid. After mixing with an acid medium to convert

sulfide ion to hydrogen sulfide, 300 µL of the sample fluid was transported into the donor reservoir

of the MBL-VP unit. Hydrogen sulfide gas diffused across the headspace and dissolved into a

fluidic zone of pure-water (200 µL) rested in the acceptor reservoir in the MBL-VP unit.

Dissolution of hydrogen sulfide resulted in an increase in the conductivity of the water fluid. The

change in conductivity was detected by using a homemade detector called „capacitively coupled

contactless conductivity detection‟ or C4D. Linear calibration was obtained for the range of 20-

200 M. with LOD and LOQ of 2.3 and 7.6 µM, respectively. The system had a good precision

with RSD < 3%.

Keywords Membraneless vaporization; Capacitively coupled contactless conductivity detection;

Sulfide; Wastewater



The Determination of Lead in Honey Using The Hanging

Mercury Dropping Electrode by An Anodic Stripping Square

Wave Voltammetric Technique

Tanin Tangkuaram1,2

*, Anchana Preechaworapun3, Juthamad Jaroenkun

2


2 Nanoscience and Nanotechnology Research Laboratory, Faculty of Science, Maejo University, Chiang Mai

50290, Thailand 3 Department of Chemistry, Faculty of Science and Technology, Pibulsongkram Rajabhat University,

Phitsanulok 65000, Thailand


This research aimed to measuring a lead content in honey product using the hanging mercury

dropping electrode (HMDE) by the anodic stripping square wave voltammetric technique (ASWV).

Under the optimal conditions of the HMDE and ASWV, it was found that the preconcentration

potential of -550 mV, preconcentration time of 50 s, amplitude potential of 50 mV, square wave

frequency of 70 Hz, step potential of 10 mV and mercury drops size of 4. The linearity was in the

concentration range of 0.1 ppm to 300 ppm with the detection limit of 0.07 ppm. The seven honey

products were tested for lead content by the developed ASWV technique and found only one

product contaminated by lead. The contaminated sample was validated by atomic absorption

spectroscopy and compared the results with the developed ASWV technique. It was found that both

accuracy and precision does not show significant different at the confidence level of 95%.

Keywords Lead, Honey, Anodic stripping square wave voltammetry



Automated On-line Spectrophotometry for Cr(VI)

Determination in Bowl Leachate Samples

Supunnee Duangthong*, Araya Angsuphat

Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai,

Songkhla 90112, Thailand


The automated on-line spectrophotometry for Cr(VI) determination by using QUIKCHEM 8500

was developed. It is based on complex formation between Cr(VI) and diphenylcarbazide (DPC)

and the complex is then measured the absorbance simultaneously at 540 nm. The parameters such

as manifold system, sample volume, flow rate of the reagents, type of carrier and concentration of

DPC were optimized. The analytical performance of the system was investigated under the

optimum conditions. The calibration curve in the range of 1-1000 ug l-1

was obtained. The relative

standard deviation for 100 ug l-1

Cr(VI) determinations (n=10) was 3.8%. The limit of detection

based on 3 times the standard deviations of blank was 1 ug L-1

. The sample frequency of 42

injections per hour was provided. The method was successfully applied to bowl leachate samples.

The recovery study was performed to validate the method. Recoveries in the range of 87-101 were

established.

Keywords Cr(VI); On-line Spectrophotometry; Leachate Samples



The Temperature Effects of Fingerprint Biomolecules on Bullet

after Shooting

Trin Pichikunchon1, Theerayut Maneeruangrit

2 and Weerachai Phutdhawong

1,2*

1Forensic Chemistry and Forensic Science Program, Faculty of Liberal Arts and Science, Kasetsart

University, Kamphaeng Saen Campus, Nakhon Pathom Province, 73140 Thailand

2Department of Chemistry, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen

Campus, Nakhon Pathom Province, 73140 Thailand


Fingerprints are considered one of the most reliable ways to identify individuals associated with

criminal cases. However, sometimes they cannot be recovered due to various environmental

factors. One of these factors is temperature, specifically high temperatures. At high temperatures

the water left by fingerprints evaporates and the amino acids denature. In this experiment, we are

focusing on latent fingerprint on bullet after shooting. The temperature ranges that we have

detected during shooting was found to be increasing 3 degree °C per 1 shooting. The latent

fingerprint on bullet were detected using mixed acid chemicals. For bullet surfaces, there are

temperatures beyond which latent prints can be recovered thus making it impossible to get an

impression. The longer the latent print is exposed to heat, the maximum temperature to visualize

that impression decreases. The denature of amino acids on each bullet were detected using GC-MS

technique. It was found that the latent fingerprint cannot be detected at 150 °C and higher. GC

peaks of biomolecules have been changed to hydrocarbons. It is reasonable to conclude that limit

of latent fingerprint detection depending on temperature increases. Further research would be

needed to solidify the exact temperature ranges.

Keywords Fingerprint, Biomolecules, Bullet, Forensic chemistry



The Development of Chemical Explosive Detection Kit

Nawinpop Panawipart1, Theerayut Maneeruangrit

2 and Weerachai Phutdhawong

1,2*

1Forensic Chemistry and Forensic Science Program, Faculty of Liberal Arts and Science, Kasetsart

University, Kamphaeng Saen Campus, Nakhon Pathom Province, 73140 Thailand

2Department of Chemistry, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen

Campus, Nakhon Pathom Province, 73140 Thailand


An explosives are substances that contain a large amount of energy stored in chemical bonds. The

energetic stability of the gaseous products and hence their generation comes from the formation of

strongly bonded species like carbon monoxide, carbon dioxide, and (di)nitrogen, which contain

strong double and triple bonds having bond strengths of nearly 1 MJ/mole. The most commercial

explosives are organic compounds containing -NO2, -ONO2 and -NHNO2 groups that, when

detonated, release gases like the aforementioned (e.g., nitroglycerin, TNT, HMX, PETN,

nitrocellulose). In this experiment, we are focusing on the development of test kit chemical

concerning to the basic physical properties of all chemicals explosive. The basic indicators were

used to identify pH of explosive solution in polar solvents. It was found that, after adding alkali

solution into polar explosive solution, the solution appeared color changed from the colorless

solution to red solution. The reason of red and blueshift effect can be identified TNT and dynamite

explosive accurately.

Keywords Chemical explosive, Detection kit, Forensic chemistry



Detection of Analytes using Toner-Based Microchips,

Electrodes Fabricated onto Acetate and Enhanced

Capabilities of Screen-Printed Electrodes

Una Crowley1,2

; Jeremy D. Glennon1; E. Moore

1,2*

1Chromatography Group, Irish Separation Science Cluster (ISSC), Department of Chemistry and the

Analytical & Biological Chemistry Research Facility (ABCRF), University College Cork, Ireland. 2 Irish Separation Science Cluster (ISSC),Sensing and Separation Group, Chemistry Department and Life

Science Interface Group, Tyndall National Institute, University College Cork, Cork, Ireland. *E-mail: [email protected]

The initial development of microfluidic devices was based on glass or quartz which is often

expensive to fabricate; however, the introduction of new types of materials, such as plastics, offered

a new way for fast prototyping and the development of disposable devices. One such microfluidic

device is based on the lamination of laser-printed polyester films using a computer, printer and

laminator. The advantages of these microchips include fast analysis times, less consumption of

samples and reagents, as well as the low-cost and rapid fabrication. The resulting toner-based

microchips demonstrated a potential viability for chemical assays, coupled with particular detection

method such as Chip-Electrophoresis-Chemiluminescence (CE-CL).

A range of micro-electrodes have been developed which are made of gold, silver and platinum by

means of patterning and deposition techniques onto acetate using the central fabrication facilities in

Tyndall National Institute. These electrodes have been designed to facilitate the integration of a 3-

electrode configuration as part of the fabrication process. Since the electrodes are on acetate the

dicing step can automatically be eliminated. This gives more control and flexibility to tailor the size

and shape of the acetate electrode depending on what detection method you are coupling them with.

The stability of these sensors has been investigated using cyclic voltammetry and potentiometry.

Following on from the generalised testing of the electrodes coupling these sensors was performed

with capillary electrophoresis.

Screen-printed electrodes (SPE) are generally seen to be far less sensitive than the more expensive

electrodes including the gold, boron-doped diamond and glassy carbon electrodes. To enhance the

sensitivity of these electrodes they were treated with carbonaceous materials and metal nano-

particles. To date the modified SPE have been shown to enhance the sensitivity by nearly 3-fold as

well as determining uric acid and dopamine simultaneously.

Keywords: Toner-based microchips; Microelectrode configuration; Acetate; Screen-printed

Electrodes; Carbon monolith; Carbon nanotubes; Metal nanoparticles.



A Water-sampling Device for Monitoring Quality

Kittiwut Khamtau,1,2

Phoonthawee Saetear,1,2

Sumonmarn Chan-Eam, 1,3

Thitirat Mantim, 1,2


Kanchana Uraisin,1,2

and Duangjai Nacapricha,1,2

1Flow Innovation-Research for Science and Technology Laboratories (FIRST Labs.) 2Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand 3Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom, 73000, Thailand

4Department of Chemistry, Faculty of Science, Srinakharinwirot University,

Sukhumvit 23 Road, Bangkok 10110, Thailand

*E-mail: [email protected] and [email protected]

A low-cost device for water sampling was designed for collection of water samples at various

depths up to 3 meters. This device is suitable for on-site sampling from river bank as well as for

underway sampling on a boat trip. The design was based on overflow method. Water sample from

canal, river or sea was continuously pumped upward through a water pipe made of polyvinyl

chloride or PVC (30 mm i.d. 35 mm o.d.) to a 10-L reservoir at a flow rate of 5 L/min. Every 2

min, previous 10-L of the sample in the reservoir was replaced by the subsequent 10-L of water.

Water in this reservoir can be drawn to analytical systems by some means of appropriate fluid

delivery for further analysis. This water sampling device was made of a pond pump. Three pieces

of common PVC plumbing pipes was attached to the inlet channel of the pump. Another piece of

PVC was attached to the outlet of the pump. A regulator valve was inserted between the pipe lines

connecting between the pump. The reservoir PVC joints and silicone sealant were used to connect

all of these components. The length of the pipe for the inlet could be extended up to 3 meters.

Keywords Water-sampling; Overflow; Sampling device; Monitoring




Electrochemical Detection and Speciation of As(III) and As(V)

by Sequential Injection using Gold-Modified Screen-Printed

Carbon Electrode

Eakkasit Punrat1, Suchada Chuanuwatanakul

1, Takashi Kaneta

3, Shoji Motomizu


1*


Chulalongkorn University, Bangkok, 10330, Thailand 2Okayama University Incubator, Okayama University, Okayama, 700-8530, Japan

3Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan


Arsenic is a toxic element known to cause a variety of adverse health effects in humans. Several

countries have reported about contamination of arsenic in environmental water. In this work, a

sequential injection (SI) system coupled with an anodic stripping voltammetry (ASV) using a gold-

modified screen-printed carbon electrode has been developed for the determination of inorganic

arsenic. Screen-printed carbon electrode (SPCE), which is well-known as a low-cost electrode, can

be prepared in our laboratory and gold is modified on the SPCE by electrochemical deposition of

Au(III) in a gold solution under a programmed SI procedure. Furthermore, SI system is an

automated flow-based system that can remove the hydrogen gas that occurs at a highly negative

potential of -1.5 V vs Ag/AgCl for reduction of As(V). Therefore, this work achieved for speciation

between As(III) and As(V) using deposition potential of -0.5 V and -1.5 V for the determination of

As(III) concentration and total arsenic concentration, respectively. The detection limits (3S/N,

n=10) in standard solutions were as low as 0.03 g L-1

and 2.3 g L-1

for As(III) and As(V),

respectively. The recovery efficiency of both of the arsenic species in three mixed standard

solutions containing As(III) and As(V) was in a good range of 95.0–104%. The proposed method is

an automated system that offers a less expensive alternative for determining trace amounts of

inorganic arsenic with high sensitivity, very good precision and reproducibility.

Keywords Arsenic detection; Sequential injection; Anodic stripping voltammetry; Gold-modified

electrode; Screen printed carbon electrode



A Microfluidic System for Catalytic Determination of

Inorganic Iodine

Prawpan Inpota1,2

, Kamil Strzelak3,4

, Wutthinan Jeamsaksiri5, Witsaroot Sripumkhai

5, Robert Koncki

3,4,

Rattikan Chantiwas1,2

, Nuanlaor Ratanawimarnwong1,6

, Duangjai Nacapricha1,2

*

1Flow Innovation-Research for Science and Technology Laboratories (FIRST labs)

2Department of Chemistry and Center of Excellence for Innovation in Chemistry Faculty of Science,

Mahidol University, Rama 6 Road, Bangkok 10400, Thailand 3University of Warsaw, Department of Chemistry, Pasteura 1, 02-093 Warsaw, Poland

4University of Warsaw, MISMaP College, Żwirki i Wigury 93, 02-089 Warsaw, Poland

5Thai Microelectronics Center (TMEC), Chachoengsao 24000, Thailand

6Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23 Road,


*E-mail:[email protected] and [email protected]

This work presents a microfluidic system for determination of total inorganic iodine. The

polydimethlysiloxane (PDMS) microfluidic system was fabricated by casting a sheet of PDMS

with microchannels (500 µm width x 300 µm depth) onto a glass substrate. The total inorganic

iodine was determined based on the catalytic effect of iodide on the reaction between Ce(IV) and

As(III). The Ce(III) product is detected by using a fluorescent probe guided from a

spectrofluorometer (ex=254 nm, em=365 nm). Other forms of iodine such as iodate is reduced to

iodide during the mixing with As(III) reagent. To optimize the condition, effects of sample

volume, flow rate and reaction time have been studied. A 3-µL of iodide standard solution was

injected into the microfluidic system at 5 µL min-1

. For determination of total inorganic iodine at

trace level, the microfluidic system was operated under the stopped-mode (180 s) prior detection.

Linear calibration was obtained in the range of 20-200 µgI L-1

(y= 0.4201x + 46.73) with a

correlation coefficient of 0.995. The proposed method has been applied to drinking water samples.

Keywords Iodine; Catalytic method; Drinking water; Microfluidic device



Electrochemical Determination of Cholesterol using Silver

Nanoparticles Modified Glassy Carbon Electrode

Siriwan Nantaphol1, Weena Siangproh

2* and Orawon Chailapakul

1,3**


Chulalongkorn University, 254 Phayathai Road, Patumwan, Bangkok 10330, Thailand

2Department of Chemistry, Faculty of Science, Srinakharinwirot University, Sukhumvit 23, Wattana, Bangkok

10110, Thailand

3Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Patumwan,



**E-mail: [email protected]

The cholesterol detection method based on the coupling of enzymatic assay and electrochemical

detection has been developed. Silver nanoparticles modified glassy carbon (AgNPs/GC) electrode

was fabricated for using as working electrode by electrodeposition technique. In this work,

hydrogen peroxide (H2O2) produced from enzymatic reaction was monitored. The electrochemical

behaviour of H2O2 at AgNPs/GC electrode was studied using cyclic voltammetry. It was found that

the reduction of H2O2 was observed at the potential around -0.4 V vs. Ag/AgCl. For determination

of cholesterol, chronoamperometry was employed. Under the optimal condition, the modified

electrode exhibited a linear range from 50 mg/dL to 350 mg/dL with a detection limit of 15.79

mg/dL. When applied to determine cholesterol concentration in bovine serum, the recovery was

obtained within the range of 99.6-100.7%. From the results, this proposed method offers a simple,

rapid and selective for detection of cholesterol.

Keywords silver nanoparticles; cholesterol; hydrogen peroxide; electrodeposition





Simple and Low Cost Moving Liquid Drop

for Down-Scaling Analysis System

Tinakorn Kanyanee1,2

*, Kate Grudpan1,2

1Center of Excellence for Innovation in Analytical Science and Technology, Chiang Mai University,

Chiang Mai 50200, Thailand 2Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, 50200, Thailand


The simple and low cost “moving liquid drop” was successfully developed and applied for down-

scaling analysis systems. Various applications of such moving liquid drop were successfully

developed for micro coulometric titration in a drop, gas sampling and analysis, and migration micro

titration. The result and advantages of the system will be discussed.

Keywords Moving liquid drop; micro titration; gas sampling and analysis (3-5 words)



A Direct and Simultaneous Flow Injection Analysis for

Iodide and Creatinine Suitable for Spot Urine

Jirayu Sitanurak,1,2

Prawpan Inpota,1,2

Thitirat Mantim,1,2


Prapin Wilairat,1,4

and Duangjai Nacapricha1,2

*

1Flow Innovation-Research for Science and Technology Laboratories (First Labs) 2Department of Chemistry and Center of Excellence for Innovation in Chemistry,

Faculty of Science, Mahidol University, Bangkok 10400, Thailand 3Department of Chemistry, Faculty of Science, Srinakharinwirot University, Bangkok 10110, Thailand

4National Doping Control Centre, Mahidol University, Bangkok 10400, Thailand


In this work, a flow injection method for direct and simultaneous analysis of iodine and creatinine

is presented. The method employed a strong anion exchange resin (Altech, USA) packed in a glass

mini-column (2.2 mm diameter and 25 mm long) for the clean-up of urine. Iodide ion was trapped

on the resin but not the creatinine. After passing through the resin, creatinine was on-lined diluted

followed by a spectrometric monitoring at 520 nm of the product formed by the reaction with

alkaline picrate. Subsequently, iodide trapped on resin was eluted from the column using 5 M

NaNO3. Selected zone of the eluate with iodide was delivered into the kinetic section of the flow

system, where iodide catalyzed a redox reaction between Ce(IV) and As(III). The change in

absorbance signal of Ce(IV) was monitored spectrometrically at 420 nm. At the optimized

condition, the system provides a reasonable throughput of 12 samples h-1

. Urine sample can be

injected and analyzed directly in this flow system without needs of pre-treatment. The detection

limits (3S/N) were satisfactorily low, i.e., 1 µg I L-1

and 12 mg creatinine L-1

and. Reasonably

good precisions were obtained for both iodide and creatinine with RSD (n= 10) of 1.5% and 5%,

respectively. The developed system is a new approach for determination of iodide in urine of an

individual person. This approach is useful for analysis of spot urine since the ratio of iodide and

creatinine is used in the evaluation of status of iodine deficiency disorder.

Keywords Iodine; Creatinine; Spot Urine; Flow injection Analysis; Solid Phase Extraction

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