Polychlorinated Dibenzo-p-dioxin Analysis from Photodegradation of

Triclosan

Jason BrennanChem 4101, Fall 2010December 10th, 2010

TriclosanCommon antimicrobial agent

used in hand soaps and hygienic products

Estimated release of 22 metric tons per year into US waters[1]

Can become chlorinated from chlorine in wastewater transport or disinfection and photodegrade into polychlorinatedibenzo-p-dioxins (PCDDs)

Photolytic half-lives of approx. 1 day during Summer months[1] http://www.dialsoap.com/

liquid_hand_soap.html

Analytes (PCDDs)

Estimations are 1.06 μg/L in US waterways [1]

Half-lives in humans range from 3-8 years [2]

Concentrations of 2.5 μg/L have been shown to cause developmental defects in aquatic life [3]

1,2,8- and 2,3,7-trichlorodibenzo-p-dioxin (TCDD)1,2,3,8-tetrachlorodibenzo-p-dioxin (TeCDD)

PCDD Detection ProblemProblem:

Polychlorinated dibenzo-p-dioxins are hypothesized to be carcinogenic compounds and the 1,2,8- 2,3,7- and 1,2,3,8-PCDDs are hypothesized to be photodegredation products of triclosan

Hypothesis:Micellar electrokinetic chromatography modified

with γ-cyclodextrin with UV absorbance detection can be used to detect the analytes in river water samples.

Micellar Electrokinetic ChromotographyReasons:

Micelles allow for neutral species detection γ-cyclodextrin modification increases sensitivityRelatively low cost/sampleQuick sample runs

Swiss Laboratory for Doping Analyses [4]

Instrumentation Agilent 7300 CECost: $50,000Instrument Parameters[5]

Fused silica capillary 40 cm effective length 50 μm I.D. 375 μm O.D.

15 kV applied voltageUV photo diode array

detector (225 nm) “Z” cell path length for

increased sensitivity10 °CLOD 0.1 ppm (S/N=3)Dynamic Range

0.3 ppm-500 ppm

Sample PreparationAqueous Sample [1] Buffer solutions [5]5 ml aqueous river

samples extracted into n-hexanes or cyclohexane

Solvent extracted into methanol

Concentrated to minimal volume for instrumental analysis

100 mM Sodioum dodecyl sulfate

50 mM γ-cyclodextrin5 M ureapH buffer

50 mM borate (pH=9.0)50 mM phosphate

(pH=2.5)

Stock solutions of chlorinated dioxins for calibration curves and spiking can be obtained from Sigma-AldrichBuffer solutions can be purchased from Agilent

Acidic SRW-CD-MEKCSRW – stacking using reverse migrating

micelles and a water plugRequires low conductivity matrix with

surfactant concentration slightly higher than critical micelle concentration

Water plug with low pH is injected into the capillary followed by the sample solution

Allows for 200 times lower LOD than CD-MEKC (20 ppm down to 0.1 ppm)

Sample Data[5]

Normal CD-MEKC SRW-CD-MEKC

ConclusionSRW-CD-MEKC allows for decreased

retention time of PCDDs and dynamic range is lowered to levels predicted in river samples

MEKC analysis allows for reasonably priced quantitative analysis of these environmental pollutants

Once these PCDDs have been confirmed in river water samples further analysis could be done to determine degradation pathway using SRW-CD-MEKC method of detection

Other Potential MethodsAdvantage Disadvantage

HPLC [1] Low LODMany column/solvent combinations for maximum resolutionReproducible

Requires flow rate and solvent optimization

GC/MS [1,7] Low LODNon-destructiveReproducibleGives structural information

Results are qualitative not quantitativeRelatively expensive instrumentation

Infrared Spectroscopy [8]

FTIR can be used for quick measurementsGives structural information

Aqueous matrix makes IR difficultResults are qualitative not quantitative

Fluorescence High sensitivity and selectivity

PCDDs do not fluoresce due to heavy atom effect

References [1] Buth, J.M., Grandbois, M., Vikesland, P.J.*, McNeill, K.*, Arnold, W.A. 2009. Aquatic

photochemistry of chlorinated triclosan derivatives: potential source of polychlorodibenzo-p-dioxins. Environ. Toxicol. Chem., 28(12) 2555-2563

[2] Geyer HJ, Schramm KW, Feicht EA, et al (2002). "Half-lives of tetra-, penta-, hexa-, hepta-, and octachlorodibenzo-p-dioxin in rats, monkeys, and humans—a critical review". Chemosphere 48 (6): 631–44.

[3] Tisha C. King Heiden, Jan Spitsbergen, Warren Heideman, and Richard E. PetersonPersistent Adverse Effects on Health and Reproduction Caused by Exposure of Zebrafish to 2,3,7,8-Tetrachlorodibenzo-p-dioxin During Early Development and Gonad DifferentiationToxicol. Sci. (2009) 109(1): 75-87

[4] Swiss Laboratory for Doping Analyses. http://www.doping.chuv.ch/en/lad_home/lad-prestations-laboratoire/lad-prestations-laboratoire-appareils/lad-prestations-laboratoire-appareils-ec.htm . Accesses Dec. 6 2010.

[5] Koji Otsuka, Hirofumi Hayashibara, Sumio Yamauchi, Joselito P. Quirino, Shigeru Terabe, Highly-sensitive micellar electrokinetic chromatographic analysis of dioxin-related compounds using on-line concentration, Journal of Chromatography, Volume 853, Issues 1-2, 20 August 1999, Pages 413-420

[6] http://www.chem.agilent.com/en-US/Products/Instruments/electrophoresis/capillary/system/pages/default.aspx. Accessed December 7th 2010.

[7] {Sommer, S.; Kamps, R.; Schumm, S.; Kleinermanns K. F. GC/FT-IR/MS Spectroscopy of Native Polychlorinated Dibenzo-p-dioxins and Dibenzofurans Extracted from Municipal Fly-Ash. Analytical Chemistry, 69, 6, 1113-1118. 1997.

[8] Charles J. Wurrey, Donald F. Gurka, Billy J. Fairless, Robert D. Kleopfer, Applications of infrared spectroscopy to dioxin analyses of environmental samples, Chemosphere, Volume 18, Issues 1-6, Chlorinated Dioxins and Related Compounds, 1989, Pages 897-902