This article was downloaded by: [Ankara Universitesi] On: 01 January 2012, At: 23:05 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK Analytical Letters Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/lanl20 Electroanalytical Methods for the Determination of Pharmaceuticals: A Review of Recent Trends and Developments Bengi Uslu a & Sibel A. Ozkan a a Faculty of Pharmacy, Department of Analytical Chemistry, Ankara University, Tandogan-Ankara, Turkey Available online: 28 Oct 2011 To cite this article: Bengi Uslu & Sibel A. Ozkan (2011): Electroanalytical Methods for the Determination of Pharmaceuticals: A Review of Recent Trends and Developments, Analytical Letters, 44:16, 2644-2702 To link to this article: http://dx.doi.org/10.1080/00032719.2011.553010 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.
Transcript
This article was downloaded by: [Ankara Universitesi]On: 01 January 2012, At: 23:05Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Analytical LettersPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/lanl20
Electroanalytical Methods for theDetermination of Pharmaceuticals:A Review of Recent Trends andDevelopmentsBengi Uslu a & Sibel A. Ozkan aa Faculty of Pharmacy, Department of Analytical Chemistry, AnkaraUniversity, Tandogan-Ankara, Turkey
Available online: 28 Oct 2011
To cite this article: Bengi Uslu & Sibel A. Ozkan (2011): Electroanalytical Methods for theDetermination of Pharmaceuticals: A Review of Recent Trends and Developments, Analytical Letters,44:16, 2644-2702
To link to this article: http://dx.doi.org/10.1080/00032719.2011.553010
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-and-conditions
This article may be used for research, teaching, and private study purposes. Anysubstantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,systematic supply, or distribution in any form to anyone is expressly forbidden.
The publisher does not give any warranty express or implied or make any representationthat the contents will be complete or accurate or up to date. The accuracy of anyinstructions, formulae, and drug doses should be independently verified with primarysources. The publisher shall not be liable for any loss, actions, claims, proceedings,demand, or costs or damages whatsoever or howsoever caused arising directly orindirectly in connection with or arising out of the use of this material.
During the past years, there has been extraordinary acceleration of progress inthe discovery, synthesis, sensitive analysis, and means of delivery of pharmaceuti-cally active compounds used in the diagnosis, prevention, and treatment of humandiseases. Analyses of smaller amounts of biological samples such as blood, serum,urine, and so forth, are often requested hence required determination methods musthave low detection and determination limits and should be applicable to smallsamples. Electrochemical techniques are powerful and versatile analytical techniquesthat offer high sensitivity, accuracy, and precision as well as large linear dynamicrange, with relatively low-cost instrumentation. After developing more sensitivepulse methods, the electroanalytical studies are more regularly used on the druganalysis in their dosage forms and especially in biological samples. However, electro-analytical techniques can easily solve many problems of pharmaceutical interest with
Received 22 September 2010; accepted 3 December 2010.
Address correspondence to Sibel A. Ozkan, Faculty of Pharmacy, Department of Analytical
Chemistry, Ankara University, 06100, Tandogan-Ankara, Turkey. E-mail: [email protected]
Analytical Letters, 44: 2644–2702, 2011
Copyright # Taylor & Francis Group, LLC
ISSN: 0003-2719 print=1532-236X online
DOI: 10.1080/00032719.2011.553010
2644
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
a high degree of accuracy, precision, sensitivity, and selectivity employing thisapproach. Some of the most useful electroanalytical techniques are based on theconcept of continuously changing the applied potentials to the electrode-solutioninterface and the resulting measured current (Kissinger and Heineman 1996; J. Wang2006; Smyth and Vos 1992; Ozkan, Uslu, and Aboul-Enein 2003; Bard and Faulkner2001; Kellner et al. 2004; Hart 1990). Most of the pharmaceutical active compoundswere found to be as electrochemically active.
The voltammetric methods used today in analytical chemistry laboratories weremade possible by recent advances in instrumentation, computerized processing ofanalytical data, and in particular, innovative electrochemists. The term working elec-trode is reserved for the electrode at which the reaction of interest occurs. Solid ormercury-based electrodes are used as working electrodes in voltammetric techniques.In general, solid electrode materials have the advantage of being more mechanicallystable, and they provide a larger anodic range than mercury-based electrodes. Also,the handling of solid electrodes is much easier such that they may readily be appliedin flow streams due to their mechanical stability and hardness (Uslu and Ozkan2007a, 2007b; J. Wang et al. 1999; Brainina and Neyman 1993; J. Wang 1988; Harvey2000; Bond 1980; Adams 1969).
The field of modified solid electrodes has become very popular with a largenumber of applications in industry, quality control of drugs and food, determinationin pharmaceutical dosage forms, environmental monitoring, and so forth. Thepotential range over which voltammetric techniques can be used depends on the solidelectrode material, the solvent, the supporting electrolyte, and pH of the studiedsolution. Solid electrode voltammetry is used largely for the oxidation of substancesat fairly positive potentials as well as for very easily reproducible substances. The per-formance of the voltammetric procedure is strongly influenced by the material of theworking electrode (Uslu and Ozkan 2007a, 2007b; J. Wang et al. 1999; J. Wang 1988;Harvey 2000; Bond 1980; Adams 1969).
Some of the most useful electroanalytical techniques are based on the conceptof continuously changing the applied potentials to the electrode-solution interfaceand the resulting measured current. The most commonly used voltammetric methodsare cyclic (CV), linear sweep (LSV), normal pulse (NPV), differential pulse (DPV),square wave (SWV), and stripping voltammetry (Kissinger and Heineman 1996; J.Wang 2006; Smyth and Vos 1992; Ozkan et al. 2003; Bard and Faulkner 2001;Kellner et al. 2004; J. Wang et al. 1999; Brainina and Neyman 1993; J. Wang1988; Harvey 2000; Gosser 1988; Koryta, Dvorak, and Kavan 1993; Bagotsky2006; Zoski 2007; Greef et al. 1990; Nicholson, 1965; Kissinger and Heineman 1983).
Modern electrochemical methods are sensitive, selective, rapid, and easy techni-ques applicable to analysis in the pharmaceutical fields and, indeed, in most areas ofanalytical chemistry, especially compared with the classical methods. As a generalrule, many of the drug active compounds can be readily oxidized or reduced incontrast to the excipients of pharmaceutical dosage forms. Electrochemical measure-ments are two-dimensional, with the potential related to qualitative properties andthe current related to quantitative properties. Thus, compounds can be selectivelydetected by electrochemical methods. This selectivity depends on the accessible poten-tial range, the number of compounds that are active in this range, and on the half-width of the single signals. The advantages of electrochemical methods are the ease
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2645
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
of sample preparation and lack of interferences from excipients in the pharmaceuticaldosage forms (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos 1992;Bard and Faulkner 2001; J. Wang 1988; Zoski 2007; Greef et al. 1990; Barker andJenkin 1952).
In addition to the analytical aspect, electrochemistry allows the establishmentof the electrochemical behavior of a given drug through mechanistic studies. In somecases, there is a relationship between voltammetry and drugs, and the knowledge ofthe mechanism of their electrode reactions can give a useful clue in elucidation of themechanism of their interaction with living cells and their fate in the human bodyafter administration as the dosage form. This is of particular interest with respectto the pharmacological knowledge of the drug. Electrochemical techniques are mostsuitable to investigate the redox properties of a new drug; this can give insights intoits metabolic fate (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos1992; Ozkan et al. 2003; Kellner et al. 2004; Hart 1990).
The purpose of this review is to give the basic information about electroanaly-tical methods, working electrodes, and their applications on pharmaceutically activecompounds in their dosage forms and in biological fluids. An attempt was made tochoose only application on drug compounds and readily available publicationsdescribing some advances in methodology and applications. The extent of this reviewmakes it impossible to quote all papers dealing with various polarographic andespecially the voltammetric determination of drugs. Thus, only selected examplesdemonstrating the applicability in biological media and=or in dosage forms of theelectroanalytical methods for various classes of drugs are presented.
CYCLIC AND LINEAR SWEEP VOLTAMMETRY
Two voltammetric techniques, LSV and CV, are the most effective and com-monly used electrochemical techniques for studying redox reactions of pharmaceu-tical active compounds. These are the most widely used for acquiring qualitativeinformation about electrochemical reactions. These techniques are not sensitiveenough for trace amount determination of pharmaceutical compounds but it is use-ful to optimize analytical conditions and it gives some important information aboutthe oxidation=reduction mechanism of drug compounds. The LSV and CV methodsalso powerful tool for the rapid determination of formal potentials, detection ofchemical reactions that precede or follow electron transfer or evaluation of electrontransfer kinetics. Both techniques require simple and inexpensive instrumentationand provide not only information on the electrochemical quantities typical of redoxprocess, but also allow investigations of chemical reactions coupled with chargetransfer step. For both techniques, a simple potential wave form that is used oftenin electrochemical experiments is the linear wave form, that is, the potential is con-tinuously changed as a linear function of time. The rate of change of potential withtime is referred to as the scan rate (Kissinger and Heineman 1996; J. Wang 2006;Smyth and Vos 1992; Ozkan et al. 2003; Kellner et al. 2004; J. Wang 1988; Harvey2000; Gosser 1988; Koryta et al. 1993; Zoski 2007; Brainina and Neyman 1993;Adams 1969; Bard and Faulkner 2001; Hart 1990).
The CV method has become a very popular technique for initial electrochemi-cal studies of new systems and has proven very useful in obtaining information about
2646 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
fairly complicated electrode reactions. Especially, the CV curves give someinformation about electron transfer kinetics and thermodynamics as well as theconsequences of electron transfer. The CV method is a potentially controlled electro-chemical experiment in which the direction of the potential is reversed at the end ofthe first scan. Thus, the waveform is usually of the form of an isosceles triangle. Thissweep is described in general by its initial, high, final potentials, and scan rate. TheCV method is the most widely used technique for acquiring qualitative informationabout electrochemical reactions. The important parameters of CV scan are themagnitude of the peak current and the peak potentials. A redox couple in which bothspecies are stable and rapidly exchange electrons with the working electrode istermed an electrochemically reversible couple. The peak current obtained at a planarelectrode for a reversible process is described by Randles-Sevcik equation (forT¼ 298� K):
Ip ¼ 2; 69� 105 n3=2 A:D1=2Cn1=2
where Ip is the peak current (Amperes); n is the number of electrons (equivalent=mol); n is the potential scan rate (V=sec); A and D are the electrode area (cm2)and the diffusion coefficient (cm2=sec), respectively; and C is the analyte concen-tration (mol=L). According to this equation, the peak current is directly proportionalto concentration and increases with the square root of the scan rate. A redox couplein which both species are stable and rapidly exchange electrons with the workingelectrode is termed an electrochemically reversible couple. The number of electronstransferred during the electrode reaction for a reversible couple can be determinedfrom the separation between the anodic and cathodic peak potentials at about0.059V=n (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos 1992; Bardand Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999; Brainina and Neyman1993; Zoski 2007; Nicholson 1965; Kissinger and Heineman 1983; Hart 1990).
In practice, the three parameters that need to be characterized are the startingpotential of the scan, the finishing potential and the scan rate in cyclic voltammetricmeasurements. An electrochemical process occurs frequently through a sequence ofsteps including:
1. The charge transfer reaction;2. The transfer of the reactant from the solution to the electrode surface and the
product from the electrode surface to the solution; and3. Possible oxidation or reduction mechanisms of the analyte and possible chemical
reactions preceding, following or the charge transfer step.
Additionally, adsorption or other surface reactions may need to be investigated.It is often the first experiment performed in an electrochemical study of a
compound, a biological material, or an electrode surface. Accordingly, the techniquehas been used widely in studying the redox mechanism of many biologically signifi-cant molecules. The result of such investigations into the redox mechanism ofdrugs may have profound effects on understanding of their in vivo redox processesof pharmaceutical activity.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2647
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
The LSV method involves monitoring current as a function of appliedpotential when a regularly varying potential is applied to the working electrode.When scanning linearly across a series of potentials, the observed current is a func-tion of potential and time. The potential limits that can be applied depend on thereference electrode, the working electrode material, and the nature and the compo-sition of the supporting electrolyte. In LSV, the potential of the working is rampedfrom an initial potential to a final potential. The potential of the working electrode ischanged linearly with time. The solution is unstirred and linear diffusion is main-tained in this technique. The scan rate direction can be signed for showing the poten-tial scan direction as negative for cathodic sweep and positive for anodic sweep. Withthis technique, the peak current is proportional to scan rate and large signals areobtained with very fast scans. The LSV method is a very useful electroanalyticaltechnique with most solid electrodes because rapid analysis times can be achievedwith about 10�6M detection limit (Kissinger and Heineman 1996; J. Wang 2006;Smyth and Vos 1992; Ozkan et al. 2003; Bard and Faulkner 2001). The maximumcurrent is called peak current and the corresponding potential is called peak poten-tial. Peak potential gives the qualitative information of the investigated compound.Also, peak current or peak height gives the quantitative amount of the compounds.
In both LSV and CV, a small stationary working electrode is dipped in anunstirred solution containing an excess of supporting electrolyte to repress migrationof charged reactants and products, so that any transfer of electroactive species to andfrom the electrode surface can occur only through diffusion. The LSV and CV meth-ods involve the application of a rapid linear potential sweep, usually between 10 and1000mVs�1. They are very useful techniques at solid electrodes as rapid analysis timescan be achieved. Also, more complicated reactions and irreversible or reversible reac-tions have been examined using the CV technique. The sweep interval can include thewhole potential range of interest, that is, for aqueous supporting electrolytes fromabout þ1.40V to �0.20V vs. Ag=AgCl electrode or be limited to shorter or longerintervals of interest and depending on working electrodes.
Analytical applications of CV and LSV can be realized using the peak current(intensity) and concentration correlation. The CV and LSV methods with inherentdetection limits of about 10�6M, are generally not sensitive enough to determinedrugs in body fluids after therapeutic doses. Actually, quantitative determinationsare usually performed solely by LSV as they are based on the response height; as aresult, no additional information is provided by CV. Both methods are well suitedfor analytical studies devoted to the rapid, simple, and accurate determination ofdrugs in raw materials, pharmaceuticals, or in biological samples. Examples of CVand LSV determination of pharmaceutically active include many classes of drugs:antibiotics, diuretics, antineoplastics, muscle relaxants, neuroleptics, analgesics,vitamins, hormones, and others. Some selected analytical data on the CV and LSVdetermination of organic compounds in pharmaceutical preparations and biologicalmedia are listed in Table 1.
Pulse Techniques
In pulse methods, the procedures are based on the application of pulse changesof potential, and the current response is measured at a suitable time relative to the
2648 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
1.SelectedexamplesofCV
andLSV
techniques
onpharm
aceuticalcompoundsin
theirdosageform
sandbiologicalmedia
Compounds
Electrochem
ical
behavior
Working
electrode
Usingmethod
LOD
orLOQ
value
Applicationmedia
References
Nifedipine
Oxidationand
Reduction
GC
CV
andLSV
8�10�5M
and
2�10�5M
Tablets
andcapsules
Senturk,Ozkan,and
Ozkan1998
Indomethacine
Reduction
HMDE
CV
10ng�m
L�1
Dosage
form
;Urine;
Plasm
a
Ali1999
Tetracycline,
Chlortetracycline,
Oxytetracycline
Reduction
HgFilm
Electrode
CV
7�10�7M,
7�10�7M,
1.5�10�6M
Raw
material
Zhouet
al.1999
Nitrofurazone
Reduction
HMDE
LSV
1�10�9M
Ointm
ent;Urine;
Serum
Khodari,Mansour,
andMersal1999
Prazosin
Reduction
Nafioncoated
CPE
CV
andLSV
—Voltammetric
behavior
Arranzet
al.1999
Buprenorphine
Oxidation
CPE
CV
2�10�7M
VialsandTab
lets
Garcia-Fernan
dez
etal.1999
ThiopentoneNa
Reduction
HMDE
LSV
1�10�8M
Dosage
form
;Urine;
Serum
Ali,Farghaly,and
Ghandour2000
Phenothiazines
(Promazine;
promethazine;
levopromazine)
Oxidation
CPE;Glass-like
carbon
LSV
2.5�10�5M;
2.5�10�5M;
6.2�10�5M
Dosage
form
sSandulescuet
al.2000
Zuclopenthixol
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Senturk
etal.2000
Ascorbic
acid
Oxidation
SPCE
CV
—Voltammetric
Behavior
Florouet
al.2000
Thiram
Oxidation
Aumicrodisc
CV
4.3�10�7M
Dosage
form
sHernandez-O
lmos
etal.2000
Tacrine
Oxidation
CPE
CV
—Voltammetric
behavior
Aparicioet
al.2000
(Continued
)
2649
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
1.Continued
Compounds
Electrochem
ical
behavior
Working
electrode
Usingmethod
LOD
orLOQ
value
Applicationmedia
References
Cefepim
eReduction
HMDE
CV
—Voltammetric
behavior
Jimenez
Palacioset
al.
2000
Buprenorphine
Oxidation
CPE
CV
—Voltammetric
behavior
Angeles
Garcia
etal.
2000
Ketoconazole
Oxidation
Pt,Au,GC
CV
—Voltammetric
behavior
Shamsipurand
Farhad
i2000
Albendazole
Oxidation
GC
LSV
3.0�10�5M
Tablets
DeOliveira
and
Stradiotto2001
Gallamine
triethiodide
Reduction
HMDE
LSV
3�10�9M
Ampoules
Ali,Ghandour,and
Abd-ElFattah2001
Isosorbidedinitrate
Reduction
Au
LSV
0.08mg
mL�1
Dosage
form
;
Arterialplasm
a;
Synthetic
serum
Parham
andZargar
2001
Lan
soprazol
Reduction
HMDE
CV
—Voltammetric
behavior
Yardım
cıandOzaltın
2001
Etodolac
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Yılmaz,
Uslu,and
Ozkan2001
a-tocopherol
Oxidation
CPE
CV
—Voltammetric
behavior
Jaiswa,Ijeri,and
Srivastava2001
OlsalazineNa
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Uslu,Yılmaz,
and
Ozkan2001
Sertraline
Reduction
HMDE
CV
andLSV
—Voltammetric
behavior
Velaet
al.2001
Melatonin
and
Pyridoxine
Oxidation
GC
CV
—Voltammetric
behavior
Uslu,Dem
ircigil,et
al.
2001
Captopril
Reduction
HMDE
LSV
0.019ngmL�1
Dosage
form
;Urine;
Serum
Ghandouret
al.2002
Ascorbic
acid
Oxidation
Modified
Al
electrode
LSV
2�10�6M
Fresh
fruitjuice;
Dosage
form
s;
plasm
a
Pournaghi-Azar,
Razm
i-Nerbin,and
Hafezi
2002
2650
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Ascorbic
acid
Electrocatalytic
oxidation
Polymer
modified
micro
electrode
LSV
1�10�4M
Dosage
form
Lupuet
al.2002
Colchicine
Reduction
HMDE
CV
1nM
Dosage
form
s;
Biologicalmedia
Kasim
2002
Nalidixic
Acid
Reduction
HMDE
CV
0.766ng�m
L�1
Dosage
form
s;
Biologicalmedia
Ibrahim
,Shehatta,
andSultan2002
Meloxicam
Reduction
SMDE
CV
—Voltammetric
behavior
Altinoz,
Nem
utlu,and
Kir2002
Vitam
inP
Reduction
HMDE
CV
2�10�9M
Tablets
Song,He,
andGuo
2002
FluvastatineNa
Oxidation
GC
CV
—Voltammetric
behavior
OzkanandUslu2002
Acetaminophen
Oxidation
BDD
thin
film
electrode
CV
10mM
Syrup
Wangfuengkanagu
l
andChailapakul
2002
S-A
denosyl-L-
Methionine
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Uslu,Ozkan,and
Aboul-Enein2002
Alfuzosine
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Uslu2002
Nitrofurantoin
Reduction
HMDE
CV
—Voltammetric
behavior
Hammam
2002
Acrivastine
Reduction
HgElectrode
CV
—Voltammetric
behavior
Fernandez
Torres
etal.
2002
Praziquantel
Reduction
HMDE
CV
—Voltammetric
behavior
M.M.Ghoneim,
Mabrouk,and
Tawfik2002
5-A
mino-salicylic
acid
Oxidation
GC
LSV
—Voltammetric
behavior
Nigovic
andSim
unic
2003a
Ambroxol
Oxidation
GC
CV
—Voltammetric
behavior
Dem
ircigilet
al.2003
Piribedil
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
UsluandOzkan2003
Melatonin
Oxidation
CPE
CV
3�10�8M
Dosage
form
sCorujo-A
ntunaet
al.
2003
(Continued
)
2651
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
1.Continued
Compounds
Electrochem
ical
behavior
Working
electrode
Usingmethod
LOD
orLOQ
value
Applicationmedia
References
Azithromycin
Oxidation
GC
CV
andLSV
—Voltammetric
behavior
Nigovic
andSim
unic
2003b
Hydrochloroquine
Reduction
GC
CV
—Voltammetric
behavior
Arguelho,Andrade,
andStradiotto2003
Sparfloxacin
Reduction
b-cyclodextrin
modified
CPE
CV
—Voltammetric
behavior
Reddy,Sreedhar,and
Reddy2003
PyridoxineHCl
(Vitamin
B6)
Oxidation
Modified
CPE
CV
1.2�10�6M
Dosage
form
sTeixeira
etal.2003
Ascorbic
acid
Oxidation
Modified
CPE
CV
6.3�10�5M
Dosage
form
sRaoof,Ojani,and
Hosseinzadeh
2003
Naproxen
Oxidation
Pt
CV
andLSV
—Voltammetric
behavior
Adhoum
etal.2003
Tiopronin
Oxidation
DiamondFilm
Electrode
CV
50mM
Dosage
form
sSiangproh,
Wangfuengk
anagu
l,
andChailapakul
2003
Tetracycline
Oxidation
Rotatinggold
discelectrode
CV
—Voltammetric
behavior
Palaharn
etal.2003
Fenofibrate
Reduction
HMDE
CV
—Voltammetric
behavior
Yardım
cıandOzaltın
2004
Chlordiazepoxide
Reduction
HgElectrode
CV
—Voltammetric
behavior
El-Hefnawey
etal.
2004
Amisulpride
Oxidation
GC
CV
—Voltammetric
behavior
Ozkan,Uslu,and
Senturk
2004
Salicylicacid
Oxidation
GC
CV
—Voltammetric
behavior
Torriero
etal.2004
Azithromycin
Oxidation
CPE
CV
—Voltammetric
behavior
Farghaly
and
Mohamed
2004
Amiloride
Reduction
HMDE
CV
—Voltammetric
behavior
Hammam
2004.
PyridoxineHCl
Oxidation
Modified
CPE
CV
andLSV
—Voltammetric
behavior
Teixeira,Marino,
etal.2004
2652
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Rifampicineand
Isoniazid
Oxidation
CPE
CV
—Voltammetric
behavior
Hammam,Beltagi,
andGhoneim
2004
Warfarin
Reduction
HMDE
CV
—Voltammetric
behavior
M.M.Ghoneim
and
Tawfik2004
Imatinib
Reduction
HMDE
CV
—Voltammetric
behavior
Hammam,El-Desoky,
Tawfik,et
al.2004
Isoprenaline
Oxidation
Modified
CPE
CV
8�10�5M
Dosageform
sBonifacioet
al.2004
AcetylsalicylicAcid
Oxidation
Enzymeelectrode
CV
Antioxidant
capacity
measured
Dosageform
sCampanella
etal.2004
Ciprofloxacin;
Azithromycin
Oxidatio
Paraffin
impregnated
graphite
electrode
CV
Qualitative
determination
Dosageform
sKomorsky-Lovricand
Nigovic
2004
Abacavir
Oxidation
GC
CV
—Voltammetric
behavior
UsluandOzkan2004
Dipyrone
Oxidation
Modified
CPE
CV
7.2�10�6M
Dosageform
sTeixeira,Marcolino,
etal.2004
Nifuroxazide
Oxidation
GC
CV
—Decomposition
product
of
nifuroxazide
Toralet
al.2004
Levonorgestrel
Reduction
HMDE
CV
—Voltammetric
behavior
M.M.Ghoneim
etal.
2004
CetirizineHCl
Oxidation
GC
CV
—Voltammetric
behavior
Gungor2004
Bromocriptine
Oxidation
GC
LSV
0.01mg
mL�1
Tab
lets
A.Radi,El-Shahawi,
andElm
ogy2005
TriprolidineHCl
Reduction
HMDE
LSV
2.64ngmL�1
Dosageform
sZayed
andHabib
2005
Tobramycine
Reduction
HMDE
LSV
3.44�10�9M
Dosageform
s;
Urine;
Serum
N.Sunet
al.2005
Trimethoprim
Reduction
HMDE
LSV
1�10�7M
Suspensiondosage
form
Carapuca,Cabral,and
Rocha2005
Aminoacid
Oxidation
ScreenPrinted
Electrode
LSV
5�10�5M
Dietary
Solution
Vasjariet
al.2005
(Continued
)
2653
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
1.Continued
Compounds
Electrochem
ical
behavior
Working
electrode
Usingmethod
LOD
orLOQ
value
Applicationmedia
References
Zafi
rlukast
Reduction
GC
andHMDE
LSV
—Voltammetric
behavior
SusluandAltinoz
2005
Cefixim
eOxidation
GC
LSV
—Voltammetric
behavior
Golcu,Dogan,and
Ozkan2005
Carvedilol
Oxidation
GC
LSV
—Voltammetric
behavior
DoganandOzkan
2005
Metoclopramide
Oxidation
Audiscmicro
electrode
CV
3.0pg�m
L�1
Dosage
form
sNorouzi,Ganjali,and
Matloobi2005
Ganciclovir
Oxidation
GC
CV
—Voltammetric
behavior
Uslu,DoganTopal,
andOzkan2005
Naproxen
Oxidation
BDDE
CV
—Voltammetric
behavior
Suryanarayananet
al.
2005
Guaifenesin
Oxidation
Pt
CV
—Voltammetric
behavior
Tapsoba,Belgaied,
andBoujlel
2005
Salbutamol
Oxidation
Audiscmicro
electrode
CV
2�10�9M
Dosage
form
s;
Biologicalsamples
Ganjaliet
al.2005
Haloperidol
Reduction
HMDE
CV
—Voltammetric
behavior
El-Desokyand
Ghoneim
2005
Captopril
Oxidation
Modified
CPE
CV
—Voltammetric
behavior
Shahrokhianet
al.
2005
Lam
ivudine
Reduction
HMDE
CV
—Voltammetric
behavior
Dogan,Uslu,et
al.
2005
Quetiapine
Oxidation
GC
LSV
—Voltammetric
behavior
Ozkan,Uslu,and
Dogan2006
N-acetylcysteine
Oxidation
CPE
LSV
6.3�10�5M
Dosage
form
sToitoSuarezet
al.
2006
Amoxicillin
Oxidation
Modified
CPE
LSV
24.8mM
Tablets
Bergaminiet
al.2006
Ceftiofur
Reduction
HMDE
LSV
6.0�10�10M
Dosage
form
s;
Bovineserum
Jacques
Barbosa
etal.
2006
Donepezil
Oxidation
GC
LSV
—Voltammetric
behavior
GolcuandOzkan2006
2654
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Ascorbic
acid
Oxidation
GC
LSV
—Voltammetric
behavior
Erdurak-K
ilic
etal.
2006
Valacyclovir
Oxidation
GC
CV
—Voltammetric
behavior
Uslu,Ozkan,and
Senturk
2006
Imipramine
Oxidation
Aumicro
electrode
LSV
14pgmL�1
Dosageform
Norouzi,Ganjali,and
Akbari-A
dergani
2006
Quetiapine
Oxidation
GC
CV
—Voltammetric
behavior
Ozkanet
al.2006
Sim
vastatin
Oxidation
GC
CV
—Voltammetric
behavior
CoruhandOzkan
2006
Ascorbic
acid
Oxidation
Modified
CPE
CV
2.9�10�5M
Dosageform
sRaoofet
al.2006
Danazol
Reduction
HMDE
CV
—Voltammetric
behavior
Alghamdi,Belal,and
Al-Omar2006
Pyrantelpamoate
Reduction
GC
CV
—Voltammetric
behavior
Jain,Jadon,and
Radhap
yari2006
Meloxicam
Oxidation
GC
LSV
0.02mM
Dosageform
s;
Urine;
Plasm
a
Farhadiand
Karimpour2007
Ethinylestradiol
Oxidation
CPE
LSV
3.0�10�8M
Tab
lets
Li2007
Tryptophan
Oxidation
Multi-walled
carbon
nanotube
modified
CPE
LSV
—Voltammetric
behavior
Shahrokhianand
Fotouhi2007
Ticlopidine
Reduction
HMDE
CV
—Voltammetric
behavior
TurkozandOnar2007
Resveratrol
Oxidation
CPE
CV
—Voltammetric
behavior
H.Zhang,Xu,and
Zheng2007
Glipizide
Reduction
HMDE
CV
—Voltammetric
behavior
E.M.Ghoneim
etal.
2007
Verap
amil
Oxidation
GC
CV
—Voltammetric
behavior
Dem
ircan,Kir,and
Ozkan2007
Ranitidine
Oxidation
Audisc
micro
electrode
CV
25pgmL�1
Dosageform
sNorouzi,Ganjali,and
Daneshgar2007
Lidocaine
Oxidation
BDDE
CV
—Voltammetric
behavior
Oliveira
etal.2007
(Continued
)
2655
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
1.Continued
Compounds
Electrochem
ical
behavior
Working
electrode
Usingmethod
LOD
orLOQ
value
Applicationmedia
References
Nabumetone
Oxidation
GC
CV
—Voltammetric
behavior
Altunet
al.2007
NaltrexoneHCl
Oxidation
Audisc
micro
electrode
CV
andLSV
8�10�4M
Tablets
Norouzi,Ganjali,
Zare,et
al.2007
D-Penicillamine
Oxidation
Modified
CPE
CV
6.04�10�4M
Capsules
Raoof,Ojani,and
Chekin
2007
L-C
ysteine
Oxidation
Modified
CPE
CV
2.0�10�6M
Tablets,
Aminoplasm
a
Serum
Raoof,Ojani,and
Beitollahi2007
Amfepramone
Reduction
HMDE
CV
—Voltammetric
behavior
DeCarvalhoet
al.
2007
Phenothiazines
Oxidation
GC
CV
1.0�10�6M
Humanbodyfluids
EnsafiandHeydari
2008
Bergenin
Oxidation
MWCNTCPE
CV
7.0�10�8M
Dosage
form
sZhuanget
al.2008
Cefdinir
Reduction
HMDE
CV
0.3�10�6M
Dosage
form
sJain,Dwivedit,and
Mishra
2008
Pentoxifylline
Oxidation
GC
CV
—Voltammetric
behavior
Hedgeand
Nandibew
oor2008
Isoniazid
Oxidation
Modified
GC
CV
1.0�10�8M
Dosage
form
sG.Yanget
al.2008
Viloxazine
Oxidation
GC
CV
—Voltammetric
behavior
Garridoet
al.2008
Leucine
Oxidation
MWCNT
modified
GC
CV
3.0�10�6M
Biologicalsamples
RezaeiandZare
2008a
Noscap
ine
Oxidation
MWCNT
modified
GC
CV
8.0�10�8M
Blood;Dosage
form
sRezaeiandZare
2008b
2656
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
PromethazineHCl
Oxidation
BDDE
CV
—Voltammetric
behavior
Ribeiro
etal.2008
Furosemide
Oxidation
Graphite
polyurethane
composite
electrode
CV
21mM
Dosage
form
sSem
aanet
al.2008
Nalidixic
Acid
Oxidation
Audisc
microelectrode
CV
0.07pgmL�1
Dosage
form
sNorouzi
etal.2008
Spironolactone
Reduction
HMDE
LSV
1.72�10�10M
Dosage
form
s;
Urine;
Serum
A.H.Al-Ghamdi
etal.2008
Opipramol
Oxidation
GC
LSV
—Voltammetric
behavior
TurhanandUslu2008
Cinnarizine
Reduction
GC
LSV
9�10�9M
Dosage
form
s;
Serum
El-Sayed
etal.2008
Pefloxacin
Oxidation
GC;BDDE
LSV
—Voltammetric
behavior
Usluet
al.2008
Methim
azole
Oxidation
Modified
CPE
LSV
—Voltammetric
behavior
Shahrokhianand
Ghalkhania
2008
Sertindole
Oxidation
GC;BDDE
LSV
—Voltammetric
behavior
Altunet
al.2009
Methotrexate
Oxidation
Modified
GC
CV
—Voltammetric
behavior
F.Wanget
al.2009
DrotaverineHCl
Reduction
HMDE
CV
—Voltammetric
behavior
Zayed
andIssa
2009
Abbreviations:
GC:glassycarbon;HMDE:Hangingmercury
dropelectrode;
CV:Cyclic
voltammetry;LSV:Linearsw
eepvoltam
metry;CPE:CarbonPaste
electrode;
SPCE:Screenprintedcarbonelectrode;
SMDE:Staticmercury
dropelectrode;
BDDE:Boron-deped
diamondelectrode;
MWCNT
CPE:Multiwalled
carbonnanotubes
carbonpasteelectrode.
2657
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
time of the pulse. Pulse technique was proposed by Barker and Gardner (1960) inorder to improve the polarographic performance and to lower the detection limitsfor electroactive species. The basis of all pulse techniques is the difference in the rateof the decay of the charging and the faradaic currents following a potential step orpulse. The charging current decays exponentially, whereas the faradaic current (for adiffusion-controlled current) decays as a function of 1=1
ffiffiffiffiffiffiffiffiffi
timep
, that is, the rate ofdecay of the charging current is considerably faster than the decay of the faradaiccurrent (Barker and Gardner 1960; Hamann, Hamnett, and Vielstich 2007). Pulsetechniques improve detection limits as they benefit from the different variation ofdiffusion and capacitive current intensities with time; when carrying out measure-ments at the pulse end, the capacitive current is practicably negligible, the value ofthe faradaic currents still being significant (Kissinger and Heineman 1996; J. Wang2006; Smyth and Vos 1992; Ozkan et al. 2003; Bard and Faulkner 2001; Kellner et al.2004; J. Wang et al. 1999; Brainina and Neyman 1993; J. Wang 1988; Harvey 2000;Gosser 1988; Koryta et al. 1993; Bagotsky 2006; Zoski 2007; Greef et al. 1990). Bysubstantially increasing the ratio between the faradaic and non-faradaic currents,pulse techniques permit convenient limit of quantitation at about 10�8M concen-tration level. The pulsed type of sampling has the advantage of an increase in sensi-tivity and better characteristics for analytical applications.
The pulse amplitude, pulse width, sample period and for some pulse techni-ques, pulse period or drop time are the important parameters of pulse techniques.Pulsed waveforms are more complex and these can be divided primarily into normalpulse, differential pulse (DPV) and square wave (SWV), voltammetry=polarography.The main weakness of pulse analysis, common to most electroanalytical techniques,is a limited ability to resolve complex systems. DP and SW have been mostly appliedpulse waveform in electrochemical drug analysis. These techniques have beenextremely useful for the determination of low amounts of electroactive compoundsin pharmaceuticals, tissues, and biological fluids. Consequently, some selected appli-cations on drug analysis which are obtained using DP and SW pulse waveform aregiven in this review.
Differential Pulse Polarography/Voltammetry (DPV)
DP is an extremely useful technique for measuring trace levels of pharmaceu-tically active compounds. The excitation waveform is basically the staircase. In DPtechnique, fixed-magnitude pulses superimposed on a linear potential ramp areapplied to the working electrode at a time just before the end of the drop. The cur-rent is sampled twice in each pulse period that once before the pulse and the secondsampling is done at the end of the pulse. The difference between these two currentvalues as a function of the potential is recorded and displayed (Barker and Gardner1960). The application of these pulses allows for discrimination of the unwantedcapacity current from the required faradaic current. When the electrode employedis a DME, the technique is called as DPP. When solid electrodes are employed thetechnique is known as DPV. DP technique is one of the most sensitive voltammetrictechniques because the charging currents are strongly discriminated and the ratio offaradaic to charging current is large (Hamann et al. 2007). Differential pulse curvesare peak shaped and thus are well suited to analytical purposes.
2658 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Due to its high sensitivity, DP method is particularly useful for trace analysis,e.g., for drug active compounds, forensic or environmental science. Because of theseadvantages and the availability of low-cost instruments, DPV is often the choice forthe determination of drug active compounds in their dosage forms and in bodyfluids. The greatest advantage of DP method is increased sensitivity, allowing lowvalue of LOD of various compounds. Several applications, based primarily on theDME and solid electrode are given in Table 2.
Square-Wave Voltammetry/Polarography (SWV)
SWV is a powerful electrochemical technique that can be applied in electroana-lytical measurements (Barker and Gardner 1960; Ozkan 2009; O’Dea, Osteryoung,and Osteryoung 1981). SWV is a large amplitude differential technique in which awaveform composed of a symmetrical square wave, superimposed on a staircase,is applied to the working electrode. The current is sampled twice during eachsquare-wave cycle, once at the end of the forward pulse, and once at the end ofthe reverse pulse. The difference between the two measurements is plotted vs. thestaircase potential. The resulting peak-shaped voltammogram displays excellent sen-sitivity and effective discrimination against background contributions (Mirceski,Komorsky-Lovric, and Lovric 2007). The SW techniques can be divided three basicgroups: the Barker, Kalusek, and Osteryoung formats. The most common form ofSW techniques is Osteryoung SWV technique.
The advantage of SWV is that a response can be found at a high effective scanrate, thus reducing the scan time. Because of this advantage, SWV is employed moreoften than other pulse techniques. There are advantages: greater speed in analysisand lower consumption of electroactive species in relation to DPV, and reducedproblems with blocking of the electrode surface. SWV is similar to DPV in that cur-rent is samples at two different times in the waveform and results in a differentialoutput. The forward current is measured at just before the down pulse is applied.The reverse current is measured at the end of the reverse pulse. The currents are mea-sured during the last few microseconds of each pulse and the difference between thecurrent measured on two successive as a net response. The net current is defined fromdifferences between forward and reverse current. The sensitivity increases from thefact that the net current is larger than either the forward or reverse components.The resulting voltammogram is peak-shaped and symmetric about the half-wavepotential. Also the sensitivity of SWV is mostly higher than that of DPV.
SWV provides several advantages to the electroanalyst. First, the applicationof the SWV waveform is that the detrimental effects of charging current are reducedand so the scan rate can be increased drastically. The second advantage of SWV isoxygen need not be excluded from the analyte solution; provided the voltammetricpeak is more cathodic than that for the reduction of oxygen, then the magnitudeof both forward and reverse current will incorporate an equal current due to thereduction of oxygen. The other advantage of SWV, the difference of currents islarger than either forward or reverse current, so the height of the peak is usuallyquite easy to read, thus increasing the accuracy.
SWV method was applied to numerous drug active compounds. Because of thesensitivity and rapidity SWV is useful for drug analysis in their dosage forms and
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2659
biological samples. The low detection and determination limits permit the analysis oftrace amount of drug compound. Various applications on pharmaceuticals andbiological samples are illustrated in Table 3.
Stripping Techniques
It is often necessary to employ some type of preconcentration step prior to theactual quantitation in the analysis of such dilute samples. This happens when the ana-lyte concentration is below the detection limit of the instrumental technique applied.Stripping voltammetric (SV) forms a subdivision of voltammetry and constitutes oneof the most important groups of electroanalytical techniques. SV is the best knownanalytical method that incorporates an electrolytic preconcentration step. The elec-troactive compound is deliberately accumulated from the solution phase onto a solidelectrode or into a liquid mercury electrode.
SV is composed of mainly four related techniques namely, anodic, cathodic,adsorptive voltammetric and potentiometric stripping. The compounds can be accu-mulated at the electrode by either faradaic (anodic, cathodic, potentiometric) ornon-faradaic (adsorption) process. Stripping methods involve a preconcentrationstep before analysis, either by forming an amalgam or complex with the particularanalyte and the electrode material or by adsorbing the substrate on the electrode sur-face (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos 1992; Ozkan et al.2003; Bard and Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999; Brainina andNeyman 1993; J. Wang 1988; Harvey 2000; Gosser 1988; Koryta et al. 1993;Bagotsky 2006; Zoski 2007; Greef et al. 1990; Uslu and Ozkan 2007a, 2007b; Bond1980; Brett and Brett 1993; A. E. Radi 2006; Ozkan 2009).
The SV techniques involve three separate steps. Initially, electrochemicalaccumulation or the deposition step of the target electroactive compounds for theaccumulation into or onto the working electrode. During this step, at a depositionpotential, the solution is usually stirred. This step is provided during a preset timeat a given electrode potential and stirring of the solution or rotating electrode thatensures a steady flow of the analyte to the electrode surface. After the accumulationstep, the stirring process is stopped. The measurement (stripping) step follows thisstep, which involves the dissolution (stripping) of the deposited analyte.
Depending on the nature of the analyte, different modes of stripping analysisare used such as linear sweep, normal pulse, differential pulse, square wave, andpotentiometric methods (Kissinger and Heineman 1996; J. Wang 2006; Smyth andVos 1992; Harvey 2000; Gosser 1988; Koryta et al. 1993; Bagotsky 2006; Zoski2007; Greef et al. 1990; Bond 1980; Brett and Brett 1993; A. E. Radi 2006; Ozkan2009). Pulse voltammetric waveforms are especially useful for the stripping step asthey effectively correct for background current contributions. Using DPV andSWV modes as the stripping technique, the contribution of the current capacitycomponent to the registered current decreases, the detection limits (LOD) isimproved, and the possibility of a rapid determination of various elements and drugcompounds at a level 10�10M appears. However, the SWV technique has the addedadvantages of a faster scan rate and increased sensitivity compare with DPV.
The SV is an excellent technique for the determination of pharmaceuticalcompounds at trace levels (Kissinger and Heineman 1996; J. Wang 2006; Smyth
and Vos 1992; Ozkan et al. 2003; Bard and Faulkner 2001; Kellner et al. 2004;J. Wang et al. 1999; Ozkan 2009). The major advantage of SV is its extremely lowdetection and determination limits (about 10�12–10�10M), which are the results ofa preconcentration step in which the analyte is accumulated onto or into the workingelectrode.
In pharmaceutical analysis, SV techniques are widely used and very popularbecause of low LOD and LOQ values, its accuracy and precision, as well as thelow cost of equipment compared to the other analytical methods.
Anodic Stripping Voltammetry (ASV)
In SV techniques, anodic stripping voltammetry (ASV) is a commonly andwidely used form. It involves the reduction of a compound or metal ion as the pre-concentration step. The preconcentration in ASV is based on electrolytic depositionand its subsequent dissolution from the electrode surface by means of an anodicpotential scan. The accumulated compounds are thus stripped out of the electrodein an order that is a function of each standard compound potential, and gives riseto anodic peak currents that are measured. The resulting peak current depends onvarious parameters of the deposition and stripping steps as well as on the character-istics of the metal ion (diffusion coefficient, number of electrons) and the electrodegeometry.
Some of the most practical electrodes for ASV are hanging mercury drop(HMDE), static mercury drop (SMDE), mercury film (MFE), carbon, iridium,platinum, gold and screen-printed electrodes (SPEs), and so forth. Newly introducedelectrodes in this area such as Bismuth film electrodes (BFEs) have also been used asan alternative to MFEs. The BFEs have low detection limits (e.g., 10�9M) and betterreproducibility results when compared with other solid electrodes.
This method has been widely used as the stripping analysis for determinationof metals in different samples such as in pharmaceutical dosage forms. The cathodicdeposition, at a controlled time and potential, is used for the preconcentration step.Generally, the deposition potential is about 0.4V more negative than standardelectrode potential (E0) for the least easily reduced metal ion to be determined.The target compounds or metal ions reach to the electrode surface by diffusion orconvention where they are reduced and concentrated as amalgams (for mercury elec-trode) or on the electrodes (solid electrodes). The solution stirring or electroderotation is performed to convection transport. This convection force is usually usedto facilitate the deposition step. The duration of the deposition step is selectedaccording to the concentration level and other requirements. The deposition timerequired is dependent on the sample concentration, between 1 and 10min periodsusually being sufficient for measurements in the range of 10�7M to 10�9M. Theobtained stripping voltammogram provides both qualitative identification (usingthe peak potential) and the quantitative information (from the peak height or area).This method has been the most widely used for stripping analysis in the determi-nation of metals. The preconcentration is done by cathodic deposition at a controlledpotential and time. In the ASV method, DPV and SWV modes are the most widelyused techniques for the stripping steps on drug and=or metal analysis in pharmaceu-tical dosage forms (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos
2668 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
1992; Ozkan et al. 2003; Bard and Faulkner 2001; Kellner et al. 2004; J. Wang et al.1999; Brainina and Neyman 1993; J. Wang 1988; Harvey 2000; Gosser 1988; Korytaet al. 1993; Bagotsky 2006; Zoski 2007; Greef et al. 1990; Nicholson 1965; Kissingerand Heineman 1983).
The remarkable sensitivity, versatility, high accuracy, precision, and low costof ASV techniques has led to its application in a large number of analytical prob-lems. The ASV techniques are also widely used for trace metals in biological samplessuch as blood, serum, plasma, urine, and tissues. Actually, ASV is most frequentlyused for metals that form amalgams with mercury. This type of application is outof the aim of this review. The only pharmaceutically active compound applicationsand metal analysis in pharmaceutical dosage forms are listed in Table 4 with theirnecessary details.
Cathodic Stripping Voltammetry (CSV)
Cathodic stripping voltammetry (CSV) is another version of stripping voltam-metry and differs in the nature of the preconcentration and stripping steps. In CSV,an anodic preconcentration step is undertaken, which is followed by a potential scantoward more negative potentials, and reduction currents are measured. It is similarto the trace analysis method ASV, except the plating step where the potential is heldat an oxidizing potential, and the oxidized species are stripped from the electrodesurface by sweeping the potential positively. The CSV method involves anodic depo-sition of an insoluble film of material on the electrode; subsequently, it is stripped offduring a negative-going potential sweep. The CSV method is the mirror image of theASV method.
The HMDE is the most commonly used working electrode for CSV; although,silver, carbon-based, platinum, and other types of solid electrodes have been used inCSV techniques (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos 1992;Ozkan et al. 2003; Bard and Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999;Brainina and Neyman 1993; J. Wang 1988; Harvey 2000; Gosser 1988; Zoski 2007).The CSV technique can be used to determine substances from insoluble salts withmercurous ion. Application of a relatively positive potential to a mercury electrodein a solution containing such substances results in the formation of an insoluble filmon the mercury electrode surface. The potential scan in the negative direction willthen strip (reduce) the deposited film into a solution. Solid electrodes such as silverand copper are less commonly used in CSV.
The preconcentration step improves selectivity, precision, and accuracy of themethod by isolating the analyte from the sample matrix, such as inactive ingredientsfrom pharmaceutical dosage forms and endogenous substances from biological sam-ples. Different voltammetric waveforms can be applied during the stripping step as inthe ASV techniques.
CSV is a widely utilized group of electroanalytical techniques for the determi-nation of trace analytes in pharmaceutical and clinical samples. Trace compoundanalyses in samples are challenging because of the low concentrations of the analytesat about between 10�9 and 10�12M. The CSV method is best suited for the determi-nation of a wide range of organic compounds especially sulfur compounds suchas penicillin, thiols, and inorganic anions, halides, sulfides, and so forth, that form
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2669
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Table
4.CSV
andASV
methodsforpharm
aceuticalcompoundsin
theirdosageform
sand=orbiologicalsamples
Compounds
Technique
Working
electrodes
Stripping
method
LOD
and=orLOQ
Applicationmedia
References
Sertraline
CSV
SMDE
SWV
1.5�10�7M
Pharm
aceuticals
Nouws,Delerue-Matos,
Barros,andRodrigu
es
2005
Rutin
CSV
HMDE
SWV
0.5nM
Pharm
aceuticals
EnsafiandHajian2006
Mn(II)
CSV
CPE
DPV
1.0�10�7M
Pharm
aceuticals
Rievajet
al.2008
Ascorbic
acid
CSV
HMDE
DPV
0.26ngmL�1
Pharm
aceuticals;human
serum
Prasadet
al.2009
Thiouracil
CSV
HMDE
DPV
2.0�10�11M
Pharm
aceuticals
Kasprzaket
al.2005
Metoclopramide
ASV
Modified
CPE
SWV
1.25ngmL�1
1.35ngmL�1
Pharm
aceuticals;human
urine
Farghaly
etal.2005
Methotrexate
(D-M
ethotrexate
and
L-M
ethotrexate)
ASV
CPE
SWV
6.79�10�10M
Pharm
aceuticals
El-Hadyet
al.2006
Sb(III)
ASV
Nanoparticle
modified
CSPE
DPV
9.44�10�10M
Pharm
aceuticals
RenedoandArcos
Martinez
2007
Sb(III)
ASV
Gold Nanoparticles
CSPE
DPV
0.2ngmL�1
Pharm
aceuticals
Renedoand
Arcos-Martinez
2007
2670
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Riboflavin
ASV
Modified
CPE
SWV
6.5�10�7M
Pharm
aceuticals
Kotkaret
al.2007
Aurothiomalate
ASV
CSPE
LSV
3.0ngmL�1
Human
urine
BergaminiandZanoni
2006
Morphine
ASV
HMDE
DPV
0.1
ppb;0.2
ppb
Human
serum
Niazi
andYazdan
ipour
2008
Pb;Cd
ASV
HMDE
DPV
—Pharm
aceuticals
Modarres-Tehrani
etal.2007
Hg(II)
ASV
Gold Nanoparticle
modified
GCE
SWV
5.62ngmL�1
Pharm
aceuticals
Abollinoet
al.2008
Hydroxyzine
ASV
GCE
SWV
1.3�10�10M
Pharm
aceuticals;
Humanserum
Beltagi,Abdallah,and
Ghomeim
2008
Amoxicillin
ASV
Nafionmodified
GCE
DPV
1.27�10�8M
Pharm
aceuticals
Ramadan,Mandil,and
Saleh2008
Sb(II)
ASV
Mercury
Film
SPE
DPV
2.0�10�10M
Pharm
aceuticals
Dominguez-R
enedo
etal.2009
Amlodipine
ASV
CPE
SWV
2.0�10�11M
Pharm
aceuticals
Kazemipouret
al.2009
Abbreviations:CSV:Cathodicstrippingvoltam
metry;ASV:Anodicstrippingvoltam
metry;SMDE:Staticmercury
dropelectrode;HMDE:Hangingmercury
drop
electrode;
CSPE:Carbonscreen
printedelectrode;
SWV:Squarewavevoltam
metry;DPV:Differentialpulsevoltam
metry;GCE:Glassycarbonelectrode;
CPE:
Carbonpasteelectrode.
2671
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
insoluble salts with the electrode material. Table 4 lists the limited pharmaceuticaland biological applications that can be obtained using the CSV technique with theirrespective detection or determination limit and the stripping mode.
Adsorptive Stripping Voltammetry (AdSV)
The improvement of the quality of drug activity requires efficient research indrug design, safety, and bioavailability. Therefore, in order to achieve these targets,highly specific, sensitive, accurate, selective, and rapid analytical methods of phar-maceutically active compound analyses are necessary. Classical stripping voltamme-try such as ASV and CSV techniques are based on an electrolytic preconcentrationstep of the analyte from the solution onto the working electrode, generally HMDE.The principle of AdSV can be compared to the other stripping techniques such asASV or CSV except that no change is transferred during the preconcentration step.Accumulation of the analyte at the electrode surface is performed at an open circuitby applying a suitable potential at which no electrochemical reactions occur for settime. The main difference between other stripping voltammetric and AdSV techni-ques is the utilization of a spontaneous adsorption process during the preconcentra-tion step. After the equilibrium time, the potential is scanned by anodic or cathodicdirection depending on the redox properties of the investigated drug compounds.The adsorptive accumulation scheme results in very effective preconcentration,allowing highly sensitive measurements (about 10�11M levels) following shortadsorption times. To attain such high sensitivity, it is essential to optimize oper-ational variables such as nature of the supporting electrolyte, pH, accumulationpotential, and time that favor strong adsorption. In drug analysis, AdSV is remark-ably sensitive, selective, and, in particular, permits the determination of trace andultratrace concentrations of numerous pharmaceutical compounds.
The disadvantage of AdSV techniques is interference from other surface activesubstances in the sample solution. Interfering effects depend on the concentrationratio between analyzed and interfering substances and on their nature (Kissingerand Heineman 1996; J. Wang 2006; Smyth and Vos 1992; Ozkan et al. 2003; Bardand Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999; Brainina and Neyman1993; J. Wang 1988; Harvey 2000; Gosser 1988; Koryta et al. 1993; Bagotsky 2006;Zoski 2007; Greef et al. 1990; Nicholson 1965; Kissinger and Heineman 1983). Thistype of effect can be minimized and the sensitivity of AdSV techniques can be pre-served by employing a shorter accumulation time, applying the correct accumulationpotential, and using appropriate solution parameters such as pH, supporting electro-lyte, and ionic strength, among others.
The AdSV technique can be carried out at practically all types of electrodesemployed in voltammetry such as HMDE, SMDE, Pt, Ru, Au, glassy carbon, dia-mond, carbon paste, wax-impregnated graphite electrodes, and others. Most adsorp-tive procedures use HMDE or SMDE for measuring reducible species, which offersthe advantages of no need for surface cleaning, reproducible surface area, and elec-trochemical response and automatic control. The solid electrodes (Au, Pt, GC, CP,diamond, etc.) are especially suitable for studying adsorbable substances that can beoxidized at the electrode, because they can be polarized to more positive potentialthan a mercury electrode that, on the other hand, can be used in a wider negative
2672 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
potential range (Kissinger and Heineman 1996; J. Wang 2006; Smyth and Vos 1992;Ozkan et al. 2003; Bard and Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999;Brainina and Neyman 1993; J. Wang 1988; Harvey 2000; Gosser 1988; Koryta et al.1993; Bagotsky 2006; Zoski 2007; Greef et al. 1990; Kissinger and Heineman 1983;Rieger 1994; Sawyer, Sobkowiak, and Robert 1995). Thus, this is preferable forstudying both oxidizable and reducible substances.
The AdSV technique is a rapid and sensitive technique that has been success-fully applied for trace measurements of important pharmaceutical compounds dueto the high selectivity and sensitivity which it provides. Also, AdSV techniques havewide concentrations, about 10�11 to 10�3M, and require low-cost equipment com-pared to other analytical methods (Kissinger and Heineman 1996; J. Wang 2006;Smyth and Vos 1992; Ozkan et al. 2003). The AdSV techniques have been success-fully applied to the determination of many pharmaceutically active compounds invarious samples such as dosage forms, biological tissues, blood, urine, amongothrees. Short adsorption times between 1 and 5min show a very effective interfacialaccumulation. Table 5 lists the selected pharmaceutical active compounds that canbe determined using AdSV techniques together with ranges of their respectiveLOD and LOQ values.
Potentiometric Stripping Analysis (PSA)
Potentiometric Stripping Analysis (PSA) is another attractive version of strip-ping analysis, and it may provide a favorable alternative to voltammetric methodsfor determination of trace amount of metals and organic drug compounds. ThePSA technique was introduced by Jagner and Graneli in 1976 based on chemical oxi-dation of metals accumulated on mercury electrodes. Also, in 1991 Jin and Wangreported on a derivative adsorptive potentiometric stripping analysis where PSAwas extended to some organic compounds and metals that cannot be electrochemi-cally preconcentrated in mercury film. Extremely low detection limits at approxi-mately the mg �L�1 level are achieved due to the preconcentration step whencompared with normal potentiometric analysis. It comprises an initial preconcentra-tion step in which the analyte is accumulated onto or into the working electrode fol-lowed by a stripping step in which the analyte is stripped back into solution. It isbased on a two basic step approach: preconcentration and analysis. The depositionstep in PSA is the similar to the ASV techniques. Nonetheless, PSA signal is notdependent on the electrode surface, where the technique can use electrodes of any size,self-optimized stripping scan rate, analysis in solutions with lower ionic strength,lower background contributions, and so forth. The difference of the PSA techniquefrom the ASV technique is the re-oxidation of the amalgamated metals that are usedin PSA. In PSA, the metal is deposited as electrolytically onto the mostly mercury filmelectrode. The constant potential is applied to the working electrode for a fixed timeduring which target metal ions in analyte solution are reduced to their elemental stateand amalgamate with and are concentrated at the mercury electrode (Kissinger andHeineman 1996; J. Wang 2006; Smyth and Vos 1992; Ozkan et al. 2003; Bard andFaulkner 2001; Kellner et al. 2004; J. Wang et al. 1999; Brainina and Neyman1993; Harvey 2000; Bagotsky 2006; Zoski 2007). By far, the most common modeof preconcentration is the accumulation of substances or metal ions by the formation
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2673
of an amalgam in a mercury drop or thin film or solid electrode surface by electrolyticreduction at a fixed potential. The selection of the applied potential during thepreconcentration step is directly effected of the selectivity. The method allowsmulti-element detection and simultaneous determination in some pharmaceuticaldosage forms such as in vitamins. Amalgam forming elements such as copper, cad-mium, lead, zinc, can be determined simultaneously in this way. Approximatelytwenty amalgam-forming metals, including Cu, Zn, Cd, Pb, Sn, Bi, Tl, In, and Mn,are easily and simultaneously analyzed by PSA based on cathodic deposition ontomercury electrodes. Also, Se, Te, As, and Hg can be analyzed at bare solid electrodessimilar to gold and carbon electrodes (J. Wang 2006; Smyth and Vos 1992; Ozkanet al. 2003; Bard and Faulkner 2001; Kellner et al. 2004; J. Wang et al. 1999; Braininaand Neyman 1993; J. Wang 1988; Harvey 2000; Gosser 1988; Koryta et al. 1993;Bagotsky 2006; Zoski 2007). When monitored as a function of time, the potentialof the electrode provides an experimental curve analogous to a normal redox titrationcurve that contains the qualitative and quantitative information. After the depositionstep, the cell is left in an open circuit, and oxidation of the metal from the electrode isaffected by an oxidant diffusing to the electrode surface; the signal recorded is poten-tial as a function of time. It may provide a favorable alternative to voltammetricmethods for determination of trace amount of metals and some organic drug com-pounds. Modern PSA equipment uses microcomputers to register fast strippingevents and to convert the wave-shaped response to a more convenient peak over a flatbaseline. The limited examples of PSA applications on the determination of pharma-ceutically active compounds in their dosage forms and in biological samples are tabu-lated in Table 5.
Abrasive Stripping Analysis (AbSV)
Abrasive Stripping Analysis (AbSV) is a newly described stripping techniqueby Scholz et al. (Scholz and Lange 1992; Scholz et al. 1991; Scholz and Lange1990; Scholz et al. 1990; Scholz et al. 1989; Scholz, Schroder, and Gulaboski2005). The technique consists of the mechanical transfer of extremely small amountsof solid compounds by abrasion onto the surface of a suitable solid electrode. In thistechnique, the traces of solid particles are abrasively transferred onto the surface ofan electrode followed by an electrochemical dissolution that is recorded as a voltam-mogram. Usually, paraffin-impregnated graphite electrodes are used with this tech-nique. The abrased material is chemically stripped off. This process is traced withconventional electrochemical measuring techniques such as DPV, SWV, and LSV.After the measurement step of AbSV, the solid electrode surface is cleaned by rub-bing it onto a smooth filter paper. It allows the rapid and easy identification of solidmaterials and avoids the dissolution of the sample and, hence, reveals informationabout the structure of the solid material, thus allowing electrochemical phase analy-sis. This technique is easily applied to many fields of solid state analysis of theelectrochemistry of solid compounds. However, the application of AbSV on thepharmaceutical or biological analysis is very limited.
Komorsky-Lovric and Nigovic (2004) worked on the identification of5-aminosalicylic acid, ciprofloxacin, and azithromycin using the AbSV method.The CV and SWV techniques were used for their qualitative determination.
2682 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
The electrochemical characterization of simvastatin has been investigated atthe graphite and mercury electrode by Komorsky-Lovric et al. (2006). The graphiteelectrode reaction was found irreversible; the mercury electrode reaction was rapidand reversible.
Nigovic, Komorsky-Lovric, and Devcic. (2008) realized the identification ofsimvastatin using the AbSV method with the SWV technique at a paraffin-impregnated graphite electrode.
CONCLUSION
Electrochemistry is a well-established and rapidly growing area with a numberof possible applications in the pharmaceutical field. Modern electrochemical meth-ods are sensitive, selective, rapid, and provide easy techniques applicable to analysesin the pharmaceutical field and, indeed, in most areas of analytical chemistry. It isapparent that the electroanalytical techniques at varying levels of sensitivity arerequired to solve analytical-pharmaceutical problems. The advantages of electro-chemical methods are the ease of sample preparation and lack of interferences fromexcipients in the pharmaceutical dosage forms.
The improvement of quality of life has stimulated considerable research in drugdesign bioavailability and safety. Thus, to reach these targets, highly sensitive, spe-cific, and rapid methods of analysis are necessary. Thanks to the progress in electro-nics and computer sciences, from which electrochemical instrumentation has gainedconsiderable benefits in terms of precision, accuracy, sensitivity, and automation, theelectroanalysis of pharmaceutically active compounds is currently actively involvedin new research areas of stripping techniques. The main advantages of the strippingelectrochemical techniques are the higher sensitivity, wide concentration ranges,applicability of both reducible and=or oxidizable organic pharmaceutically activecompounds, and the low-cost equipment compared with the other analytical meth-ods. They are rapid techniques that have been successfully applied for trace measure-ments of important pharmaceutically active compounds due to the high sensitivityand selectivity that they provide. The aim of this review is to show that, for someanalytes and some types of matrices, especially drug dosage forms and endogenoussubstances, electroanalytical methods at all type of electrodes may be the bestmethod and can successfully compete with more widespread separation and spectro-metric methods.
REFERENCES
Abbaspour, A., and R. Mirzajani. 2007. Electrochemical monitoring of piroxicam in differentpharmaceutical forms with multi-walled carbon nanotubes paste electrode. J. Pharm.Biomed. Anal. 44: 41–48.
Abdel Ghani, N. T., M. A. El-Ries, and M. A. El-Shall. 2007. Validated polarographicmethods for the determination of certain antibacterial drugs. Anal. Sci. 23: 1053–1058.
Abollino, O., A. Giacomino, M. Malandrino, G. Piscionieri, and E. Mentasti. 2008. Determi-nation of mercury by anodic stripping voltammetry with a gold nanoparticle-modifiedglassy carbon electrode. Electroanalysis 20: 75–83.
Adams, R. N. 1969. Electrochemistry at Solid Electrodes. New York: Marcel Dekker.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2683
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Adhoum, N., and L. Monser. 2005. Determination of trimebutine in pharmaceuticals by differ-ential pulse voltammetry at a glassy carbon electrode. J. Pharm. Biomed. Anal. 38: 619–623.
Adhoum, N., L. Monser, M. Toumi, and K. Boujlel. 2003. Determination of naproxen inpharmaceuticals by differential pulse voltammetry at a platinum electrode. Anal. Chim. Acta495: 69–75.
Alghamdi, A. F. 2009. A study of adsorptive stripping voltammetric behavior of ofloxacineantibiotic in the presence of Fe(III) and its determination in tablets and biological fluids.J. Saudi Chem. Soc. 13: 231–235.
Alghamdi, A. H., A. F. Al-Ghamdi, and M. A. Al-Omar. 2008. Electrochemical studies andsquare-wave adsorptive stripping voltammetry of spironolactone drug.Anal. Lett. 41: 90–103.
Alghamdi, A. H. 2008. Square-wave adsorptive stripping voltammetric determination of anantihistamine drug astemizole. Chem. Pap. 62: 339–344.
Alghamdi, A. H., A. F. Alghamdi, and M. A. Al-Omar. 2009. A study of stripping voltam-metric behaviour of cefadroxil antibiotic in the presence of Cu(II) and its determinationin pharmaceutical formulation. Port. Electrochim. Acta 27: 645–655.
Alghamdi, A. H., F. F. Belal, and M. A. Al-Omar. 2006. Square-wave adsorptive strippingvoltammetric determination of danazol in capsules. J. Pharm. Biomed. Anal. 41: 989–993.
Ali, A. M. M. 1999. Cathodic adsorptive stripping voltammetric determination of theanti-inflammatory drug indomethacin. J. Pharm. Biomed. Anal. 18: 1005–1012.
Ali, A. M. M., O. A. Farghaly, and M. A. Ghandour. 2000. Determination of thiopentonesodium in aqueous and biological media by cathodic stripping voltammetry. Anal. Chim.Acta 412: 99–110.
Ali, A. M. M., M. A. Ghandour, and M. M. Abd-El Fattah. 2001. Cathodic adsorptive strip-ping voltammetric determination of muscle relaxant: Gallamine triethiodide (flaxedil). J.Pharm. Biomed. Anal. 25: 31–37.
Altinoz, S., E. Nemutlu, and S. Kir. 2002. Polarographic behaviour of meloxicam and itsdetermination in tablet preparations and spiked plasma. Farmaco. 57: 463–468.
Altınoz, S., and I. Suslu. 2005. Determination of pantoprazole in pharmaceutical formulationsand human plasma by square-wave voltammetry. Anal. Lett. 38: 1389–1404.
Altun, Y., B. Dogan, S. A. Ozkan, and B. Uslu. 2007. Development and validation of voltam-metric techniques for nabumeton in pharmaceutical dosage form, human serum and urine.Acta Chim. Slov. 54: 287–294.
Altun, Y., B. D. Topal, B. Uslu, and S. A. Ozkan. 2009. Anodic behavior or sertindole and itsvoltammetric determination in pharmaceuticals and human serum using glassy carbon andboron-doped diamond electrodes. Electrochim. Acta 54: 1893–1903.
Angeles Garcia, M. F., A. M. Teresa Fernandez, and A. Costa Garcia. 2000. Determination ofbuprenorphine in pharmaceuticals and human urine by adsorptive stripping voltammetry inbatch and flow systems. Electroanalysis 12: 483–489.
Aparicio, I., M. Callejon, J. C. Jimenez, M. A. Bello, and A. Guiraum. 2000. Electrochemicaloxidation at carbon paste electrode of tacrine and 1-hydroxytacrine and differential pulsevoltammetric determination of tacrine in pharmaceuticals and human urine. Analyst 125:2016–2019.
Arguelho, M. L. P. M., J. F. Andrade, and N. R. Stradiotto. 2003. Electrochemical study ofhydroxychloroquine and its determination in plaquenil by differential pulse voltammetry. J.Pharm. Biomed. Anal. 32: 269–275.
Arguelho, M. L. P. M., M. V. B. Zanoni, and N. R. Stradiotto. 2005. Electrochemicaloxidation and voltammetric determination of the antimalaria drug primaquine. Anal. Lett.38: 1415–1425.
Arranz, A., S. F. De Betono, C. Echevarria, J. M. Moreda, A. Cid, and J. F. Arranz Valentin.1999. Voltammetric and spectrophotometric techniques for the determination of the antihy-pertensive drug prazosin in urine and formulations. J. Pharm. Biomed. Anal. 21: 797–807.
2684 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Aslanoglu, M., A. Kutluay, S. Karabulut, and S. Abbasoglu. 2008. Voltammetricdetermination of adrenaline using a poly (1-methylpyrrole) modified glassy carbon electrode.J. Chin. Chem. Soc. 55: 794–800.
Bagotsky, V. S. 2006. Fundamentals of Electrochemistry, 2nd Ed. New Jersey: Wiley-Interscience Pub.
Bard, A. J., and L. R. Faulkner. 2001.ElectrochemicalMethods, Fundamentals and Applications,2nd Ed. New York: Wiley.
Barker, G. C., and A. W. Gardner. 1960. Pulse polarography. Fresenius Z. Anal. Chem. 173:79–83.
Barker, G. C., and I. L. Jenkin. 1952. Square-wave polarography. Analyst 77: 685–696.Beltagi, A. M. 2008. Development and validation of an adsorptive stripping voltammetricmethod for the quantification of vincamine in its formulations and human serum using anujol-based carbon paste electrode. Chem. Pharm. Bull. 56: 1651–1657.
Beltagi, A. M. 2009. Utilization of a montmorillonite-Ca-modified carbon paste electrode forthe stripping voltammetric determination of diflunisal in its pharmaceutical formulationsand human blood. J. Appl. Electrochem. 39: 2375–2384.
Beltagi, A. M., O. M. Abdallah, and M. M. Ghoneim. 2007. Determination of piroxicam inpharmaceutical formulations and human serum by square-wave stripping voltammetry.Chem. Anal.-Warsaw 52: 387–398.
Beltagi, A. M., O. M. Abdallah, and M. M. Ghoneim. 2008. Development of a voltammetricprocedure for assay of the antihistamine drug hydroxyzine at a glassy carbon electrode:quantification and pharmacokinetic studies. Talanta 74: 851–859.
Beltagi, A. M. R., M. A. El-Attar, and E. M. Ghoneim. 2007. Adsorptive stripping voltam-metric determination of the anti-inflammatory drug tolmetin in bulk form, pharmaceuticalformulation and human serum. Cent. Eur. J. Chem. 5: 835–845.
Beltagi, A. M., H. S. El-Desoky, and M. M. Ghoneim. 2007. Quantification of terbutaline inpharmaceutical formulation and human serum by adsorptive stripping voltammetry at aglassy carbon electrode. Chem. Pharm. Bull. 55: 1018–1023.
Bergamini, M. F., and M. V. B. Zanoni. 2006. Anodic stripping voltammetric determination ofaurothiomalate in urine using a screen-printed carbon electrode.Electroanalysis 15: 1457–1462.
Bergamini, M. F., D. P. Santos, and M. V. B. Zanoni. 2010. Determination of isoniazid inhuman urine using screen-printed carbon electrode modified with poly-l-histidine. Bioelec-trochem. 77: 133–138.
Bergamini, M. F., M. F. S. Teixeira, E. R. Dockal, N. Bocchi, and T. G. E. Cavalheiro. 2006.Evaluation of different voltammetric techniques in the determination of amoxicillin using acarbon modified with [N-N-ethylenbis(salicylideaminato)]oxıvanadium (IV). J. Electrochem.Soc. 153: E94–E98.
Bond, A. M. 1980. Modern Polarographic Methods in Analytical Chemistry. New York:
Marcel Dekker.Bonifacio, V. G., L. H. Marcolino, Jr., M. F. S. Teixeira, and O. Fatibello-Filho. 2004.Voltammetric determination of isoprenaline in pharmaceutical preparations using acopper(II) hexacyanoferrate(III) modified carbon paste electrode. Microchem. J. 78: 55–59.
Brainina, Kh. Z., and E. Neyman. 1993. In Electroanalytical Stripping Methods. Vol. 26, ed.J. D. Winefordner. New York: Wiley.
Brett, C. M. A., and A. M. Oliveira Brett. 1993. Electrochemistry, Principles, Methods andApplications. Oxford: Oxford University Press.
Buckova, M., P. Grundler, and G. U. Flechsig. 2005. Adsorptive stripping voltammetricdetection of daunomycin at a bismuth bulk electrode. Electroanalysis 17: 440–444.
Burgoa Calvo, M. E., O. Domınguez Renedo, and M. J. Arcos Martınez. 2005. Optimizationof the experimental parameters in the determination of lamotrigine by adsorptive strippingvoltammetry. Anal. Chim. Acta 549: 61–67.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2685
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Burgoa Calvo, M. E., O. Domınguez Renedo, and M. J. Arcos Martınez. 2007. Determinationof lamotrigine by adsorptive stripping voltammetry using silver nanoparticle-modifiedcarbon screen-printed electrodes. Talanta 74: 59–64.
Cabanillas, A. G., M. I. R. Caceres, M. A. Martınez Canas, J. M. Ortiz Burguillos, and T. G.Dıaz. 2007. Square wave adsorptive stripping voltametric determination of the mixture ofnalidixic acid and its main metabolite (7-hydroxymethylnalidixic acid) by multivariatemethods and artificial neural network. Talanta 72: 932–940.
Calvo, M. E. B., O. D. Renedo, and M. J. A. Martınez. 2005. Optimization of the experi-mental parameters in the determination of lamotrigine by adsorptive stripping voltammetry.Anal. Chim. Acta. 549: 74–80.
Calvo, M. E. B., O. Domınguez Renedo, and M. J. Arcos Martınez. 2007. Determination ofoxcarbazepine by square wave adsorptive stripping voltammetry in pharmaceutical prepara-tions. J. Pharm. Biomed. Anal. 43: 1156–1160.
Campanella, L., A. Bonanni, D. Bellantoni, G. Favero, and M. Tomassetti. 2004. Comparisonof fluorimetric, voltammetric and biosensor methods for the determination of total antiox-idant capacity of drug products containing acetylsalicylic acid. J. Pharm. Biomed. Anal. 36:91–99.
Carapuca, H. M., D. J. Cabral, and L. S. Rocha. 2005. Adsorptive stripping voltammetry oftrimethoprim: Mechanistic studies and application to the fast determination in pharmaceu-tical suspensions. J. Pharm. Biomed. Anal. 38: 364–369.
Cardoso, C. E., P. A. M. Farias, R. O. R. Martins, and R. Q. Aucelio. 2005. Square-wave anddifferential-pulse adsorptive stripping voltammetry for ultra-trace determination of theanti-angiogenic drug thalidomide in the presence of concomitant drugs. Anal. Lett. 38:1259–1274.
Chen, K., J. Chen, M. Guo, Z. Li, and S. Yao. 2006. Electrochemical behavior of MCF-7cells on carbon nanotube modified electrode and application in evaluating the effect of5-Fluorouracil. Electroanalysis 18: 1179–1185.
Coruh, O., and S. A. Ozkan. 2006. Determination of the antihyperlipidemic simvastatin byvarious voltammetric techniques in tablets and serum samples. Pharmazie 61: 285–290.
Corujo-Antuna, J. L., E. M. Abad-Villar, M. T. Fernadez-Abedul, and A. Costa-Garcia.2003. Voltammetric and flow amperometric methods for the determination of melatoninin pharmaceuticals. J. Pharm. Biomed. Anal. 31: 421–429.
Costa, C. D., P. R. B. Miranda, B. Hazra, M. Das Sarma, R. D. S. Luz, L. T. Kubota, andM. O. F. Goulart. 2006. Development of a voltammetric sensor for diospyrin determinationin nanomolar concentrations. Talanta 68: 1378–1383.
Daneshgar, P., P. Norouzi, and M. R. Ganjali. 2009. Application of a continuous square-wavepotential program for sub nano molar determination of ketotifen. Chem. Pharm. Bull. 57:117–121.
Daneshgar, P., P. Norouzi, M. R. Ganjali, A. Ordikhani-Seyedlar, and H. A. Eshraghi. 2009.Dysprosium nanowire modified carbon paste electrode for determination of levodopa usingfast fourier transformation square-wave voltammetry method. Colloid Surf. B 68: 27–32.
De Carvalho, L. M., P. C. Do Nascimento, D. Bohrer, D. Correia, A. V. De Bairros, V. J.Pomblumc, and S. G. Pomblum. 2007. Voltammetric behavior of amfepramone (diethylpro-pion) at the hanging mercury dropelectrode and its analytical determination in pharmaceu-tical formulations. J. Brazilian Chem. Soc. 18: 789–796.
De Lima-Neto, P., A. N. Correia, R. R. Portela, M. da Silva Juliao, G. F. Linhares, Jr., and J.E. S. de Lima. 2010. Square wave voltammetric determination of nitrofurantoin in pharma-ceutical formulations on highly boron-doped diamond electrodes at different boron-dopingcontents. Talanta 80: 1730–1736.
De Oliveira, M. F., and N. R. Stradiotto. 2001. Voltammetrıc assay of albendazole ınpharmaceutıcal dosage forms. Anal. Lett. 34: 377–387.
2686 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
De Toledo, R. A., M. Castilho, and L. H. Mazo. 2005. Determination of dipyridamole inpharmaceutical preparations using square wave voltammetry. J. Pharm. Biomed. Anal.36: 1113–1117.
Demircan, S., S. Kir, and S. A. Ozkan. 2007. Electroanalytical characterization of verapamil andits voltammetric determination in pharmaceuticals and human serum.Anal. Lett. 40: 1177–1195.
Demircigil, B. T., B. Uslu, Y. Ozkan, S. A. Ozkan, and Z. Senturk. 2003. Voltammetricoxidation of ambroxol and application to ıts determination in pharmaceuticals and in drugdissolution studies. Electroanalysis 15: 230–234.
Diculescu, V. C., M. Vivan, and A. M. O. Brett. 2006. Voltammetric behavior of antileukemiadrug glivec. Part II – redox processes of glivec electrochemical metabolite. Electroanalysis18: 1808–1814.
Dogan, B., D. Canbaz, S. A. Ozkan, and B. Uslu. 2006. Electrochemical methods fordetermination of protease inhibitor indinavir sulfate in pharmaceutics and human serum.Pharmazie. 61: 409–413.
Dogan, B, A. Golcu, M. Dolaz, and S. A. Ozkan. 2009a. Electrochemical behaviour of thebactericidal cefoperazone and its selective voltammetric determination in pharmaceuticaldosage forms and human serum. Curr. Pharm. Anal. 5: 179–189.
Dogan, B., A. Golcu, M. Dolaz, and S. A. Ozkan. 2009b. Anodic oxidation of antibacterialdrug cefotaxime sodium and its square wave and differential pulse voltammetric determi-nation in pharmaceuticals and human serum. Curr. Pharm. Anal. 5: 197–207.
Dogan, B., and S. A. Ozkan. 2005. Electrochemical behavior of carvedilol and its adsorptivestripping determination in dosage forms and biological fluids. Electroanalysis 17: 2074–2083.
Dogan, B., S. A. Ozkan, and B. Uslu. 2005. Electrochemical characterization of flupenthixoland rapid determination of the drug in human serum and pharmaceuticals by voltammetry.Anal. Lett. 38: 641–656.
Dogan, B., S. Tuncel, B. Uslu, and S. A. Ozkan. 2007. Selective electrochemical behavior ofhighly conductive boron-doped diamond electrodes for fluvastatin sodium oxidation. Diam.Relat. Mat. 16: 1695–1704.
Dogan, B., B. Uslu, S. A. Ozkan, and P. Zuman. 2008. Electrochemical determination of HIVdrug abacavir based on its reduction. Anal. Chem. 80: 209–216.
Dogan, B., B. Uslu, S. Suzen, and S. A. Ozkan. 2005. Electrochemical evaluation of nucleosideanalogue lamivudine in pharmaceutical dosage forms and human serum. Electroanalysis 17:1886–1894.
Dogan-Topal, B., B. Bozal, B. T. Demircigil, B. Uslu, and S. A. Ozkan. 2009. Electroanalyticalstudies and simultaneous determination of amlodipine besylate and atorvastatine calcium inbinary mixtures using first derivative of the ratio-voltammetric methods. Electroanalysis 21:2427–2439.
Dogan-Topal, B., B. Uslu, and S. A. Ozkan. 2007. Investigation of electrochemical behaviorof lipid lowering agent atorvastatin calcium in aqueous media and its determination frompharmaceutical dosage forms and biological fluids using boron-doped diamond and glassycarbon electrodes. Comb. Chem. High T. Scr. 10: 571–582.
Dogan-Topal, B., B. Uslu, and S. A. Ozkan. 2009. Voltammetric studies on the HIV-1inhibitory drug Efavirenz: The interaction between dsDNA and drug using electrochemicalDNA biosensor and adsorptive stripping voltammetric determination on disposable pencilgraphite electrode. Biosens. Bioelectron. 24: 2358–2364.
Dominguez-Renedo, O., and M. J. Arcos-Martinez. 2007. Anodic stripping voltammetry ofantimony using gold nanoparticle-modified carbon screen-printed electrodes. Anal. Chim.Acta. 589: 255–260.
Dominguez-Renedo, O., M. E. B. Calvo, and M. J. Arcos-Martinez. 2008. Determination oflamotrigine in pharmaceutical preparations by adsorptive stripping voltammetry usingscreen printed electrodes. Sensors 8: 4201–4212.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2687
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Dominguez-Renedo, O., M. J. G. Gonzalez, and M. J. Arcos-Martinez. 2009. Determinationof antimony (III) in real samples by anodic stripping voltammetry using a mercury filmscreen-printed electrode. Sensors 9: 219–231.
El-Desoky, H. S. 2005. A validated voltammetric procedure for quantification of the antifungaldrug griseofulvin in bulk form, tablets, electrode. Anal. Lett. 38: 1783–1802.
El-Desoky, H. S. 2009. Stability indicating square-wave stripping voltammetric method fordetermination of gatifloxacin in pharmaceutical formulation and human blood. J. Brazil.Chem. Soc. 20: 1790–1799.
El-Desoky, H. S., and M. M. Ghoneim. 2005. Assay of the anti-psychotic drug haloperidol inbulk form, pharmaceutical formulation and biological fluids using square-wave adsorptivestripping voltammetry at a mercury electrode. J. Pharm. Biomed. Anal. 38: 543–550.
El-Desoky, H. S., E. M. Ghoneim, and M. M. Ghoneim. 2005. Voltammetric behavior andassay of the antibiotic drug cefazolin sodium in bulk form and pharmaceutical formulationat a mercury electrode. J. Pharm.Biomed. Anal. 39: 1051–1056.
El-Hady, D. A., M. M. Seliem, R. Gotti, and N. A. El-Maali. 2006. Novel voltammetricmethod for enantioseparation of racemic methotrexate: Determination of its enantiomericpurity in some pharmaceuticals. Sensor Actuat. B 113: 978–988.
El-Hefnawey, G. B., I. S. El-Hallog, E. M. Ghoneim, andM.M. Ghoneim. 2004. Voltammetricbehavior and quantification of the sedative-hypnotic drug chlordiazepoxide in bulk form,pharmaceutical formulation and human serum at a mercury electrode. J. Pharm. Biomed.Anal. 34: 75–86.
El-Maali, N. A, A. H. Osman, A. A. M. Aly, and G. A. A. Al-Hazmi. 2005. Voltammetricanalysis of Cu(II), Cd(II) and Zn(II) complexes and their cyclic voltammetry with severalcephalosporin antibiotics. Bioelectrochem. 65: 95–104.
El-Ries, M. A., A. A. Wassel Abdel, N. T. Ghani, and M. A. El-Shall. 2005. Electrochemicaladsorptive behavior of some fluoroquinolones at carbon paste electrode. Anal. Sci. 21:1249–1254.
El-Ries, M. A. N., G. G. Mohamed, and A. K. Attia. 2008. Electrochemical determination ofthe antidiabetic drug repaglinide. J. Pharm. Soc. Japan 128: 171–177.
El-Said, W. A., C. H. Yea, H. Kim, B. K. Oh, and J. W. Choi. 2009. Cell-based chip for thedetection of anticancer effect on HeLa cells using cyclic voltammetry. Biosens. Bioelectron.24: 1259–1265.
El-Sayed, G. O., S. A. Yasin, and A. A. El-Badawy. 2008. Voltammetric behavior and determi-nation of cinnarizine in pharmaceutical formulations and serum. Anal. Lett. 41: 3021–3033.
El-Sayed, G. O., S. A. Yasin, A. A. El-Badawy, and A. Azza. 2010. Determination of secni-dazole in tablets and human serum by cathodic adsorptive stripping voltammetry. Arab. J.Chem. 3: 167–172.
El-Shahawi, M. S., A. S. B. Ashammakh, and T. El-Mogy. 2006. Determination of trace levelsof diosmin in a pharmaceutical preparation by adsorptive stripping voltammetry at a glassycarbon electrode. Anal. Sci. 22: 1351–1354.
Ensafi, A. A., and R. Hajian. 2006. Determination of rutin in pharmaceutical compounds andtea using cathodic adsorptive stripping voltammetry. Electroanalysis 18: 579–585.
Ensafi, A. A., and R. Hajian. 2008. Determination of losartan and triamterene in pharmaceu-tical compounds and urine using cathodic adsorptive stripping voltammetry. Anal. Sci. 24:1449–1454.
Ensafi, A. A., and E. Heydari. 2008. Determination of some phenothiazines compounds inpharmaceuticals and human body fluid by electrocatalytic oxidation at a glassy carbonelectrode using methylene blue as a mediator. Anal. Lett. 41: 2487–2502.
Ensafi, A. A., T. Khayamian, and M. Taei. 2009. Determination of ultra trace amount ofenrofloxacin by adsorptive cathodic stripping voltammetry using copper(II) as an intermedi-ate. Talanta 78: 942–948.
2688 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Erdurak-Kilic, C. S., B. Uslu, B. Dogan, U. Ozgen, S. A. Ozkan, and M. Coskun. 2006.Anodic voltammetric behavior and selective determination of ascorbic acid in pharmaceu-tical dosage forms and some rosa species of Turkey. J. Anal. Chem. 61: 1113–1120.
Farghaly, O. A. E. M., and N. A. L. Mohamed. 2004. Voltammetric determination of azithro-mycin at the carbon paste electrode. Talanta 62: 531–538.
Farghaly, O. A., M. A. Taher, A. H. Naggar, and A. Y. El-Sayed. 2005. Square wave anodicstripping voltammetric determination of metoclopramide in tablet and urine at carbon pasteelectrode. J. Pharm. Biomed. Anal. 38: 14–20.
Farhadi, K., and A. Karimpour. 2007. Electrochemical determination of meloxicam inpharmaceutical preparation and biological fluids using oxidized glassy carbon electrodes.Chem. Pharm. Bull. 55: 638–642.
Farhadi, K., R. H. Yamchi, and R. Sabzi. 2007. Electrochemical study of interaction betweenclozapine and DNA and its analytical application. Anal. Lett. 40: 1750–1762.
Fernandez Torres, R., M. Callejon Mochon, J. C. Jimenez Sanchez, M. A. Bello Lopez, andA. Guiraum Perez. 2002. Electrochemical behaviour and determination of acrivastine inpharmaceuticals and human urine. J. Pharm. Biomed. Anal. 30: 1215–1222.
Fernandez-Torres, R., M. Villar Navarro, M. Bello Lopez, M. Callejon Mochon, andJ. C. Jimenez Sanchez. 2008. Urea as new stabilizing agent for imipenem determination.Electrochemical study and determination of imipenem and its primary metabolite in humanurine. Talanta 7: 241–248.
Florou, A. B., M. I. Prodromidis, S. M. Tzouwara-Karayanni, and M. I. Karayannis. 2000.Fabrication and voltammetric study of lanthanum 2,6-dichlorophenolindophenolchemically modified screen printed electrodes: Application for the determination of ascorbicacid. Anal. Chim. Acta 423: 107–114.
Ganjali, M. R., P. Norouzi, M. Ghorbani, and A. Sepehri. 2005. Fourier transform cyclicvoltammetric technique for monitoring ultratrace amounts of salbutamol at gold ultramicroelectrode in flowing solutions. Talanta 66: 1225–1233.
Gao, W., J. Song, and N. Wu. 2005. Voltammetric behavior and square-wave voltammetricdetermination of trepibutone at a pencil graphite electrode. J. Electroanal. Chem. 576:1–7.
Garcia-Fernandez, M. A., M. T. Fernandez-Abedul, and A. Costa-Garcia. 1999. Voltam-metric study and determination of buprenorphine in pharmaceuticals. J. Pharm. Biomed.Anal. 21: 809–815.
Garrido, E. M. P. J., J. M. P. J. Garrido, M. Esteves, A. Santos-Silva, M. P. M. Marques,and F. Borges. 2008. Voltammetric and dft studies on viloxazine: analytical applicationto pharmaceuticals and biological fluids. Electroanalysis 20: 1454–1462.
Gazy, A. A., H. Mahgoub, E. F. Khamis, R. M. Youssef, and M. A. El-Sayed. 2006. Differ-ential pulse, square wave and adsorptive stripping voltammetric quantification of tianeptinein tablets. J. Pharm. Biomed. Anal. 41: 1157–1163.
Ghalkhani, M., and S. Shahrokhian. 2010. Application of carbon nanoparticle=chitosanmodified electrode for the square-wave adsorptive anodic striping voltammetric determi-nation of niclosamide. Electrochem. Commun. 12: 66–69.
Ghandour, M. A., E. A. Kasım, M. T. El-Haty, and M. M. Ahmed. 2002. Cathodıc strippingvoltammetry of the antihypertensive drug captopril in both aqueous and biological media.Anal. Lett. 35: 239–256.
Ghoneim, E. M. 2007. Electroreduction of the muscle relaxant drug dantrolene sodium at themercury electrode and its determination in bulk form and pharmaceutical formulation.Chem. Pharm. Bull. 55: 1483–1488.
Ghoneim, E. M., M. A. El-Attar, and M. M. Ghoneim. 2009. Adsorptive cathodic strippingvoltammetric determination of dexamethasone in formulations and biological fluids. J.AOAC Int. 92: 597–603.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2689
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Ghoneim, E. M., M. A. El-Attar, E. Hamam, and P. Y. Khashaba. 2007. Stripping voltam-metric quantification of the anti-diabetic drug glipizide in bulk form and pharmaceuticalformulation. J. Pharm. Biomed. Anal. 43: 1465–1469.
Ghoneim, E. M., and H. S. El-Desoky. 2010. Electrochemical determination of methocarba-mol on a montmorillonite-Ca modified carbon paste electrode in formulation and humanblood. Bioelectrochem. 79: 241–247.
Ghoneim, E. M., H. S. El-Desoky, and M. M. Ghoneim. 2006. Adsorptive cathodic strippingvoltammetric assay of the estrogen drug ethinylestradiol in pharmaceutical formulation andhuman plasma at a mercury electrode. J. Pharm. Biomed. Anal. 40: 255–261.
Ghoneim, M. M., A. M. Abushoffa, Y. I. Moharram, and H. S. El-Desoky. 2007. Voltamme-try and quantification of the contraceptive drug norethisterone in bulk form and pharma-ceutical formulation. J. Pharm. Biomed. Anal. 43: 499–505.
Ghoneim, M. M., W. Baumann, E. Hammam, and A. Tawfik. 2004. Voltammetric behaviorand assay of the contraceptive drug levonorgestrel in bulk, tablets, and human serum at amercury electrode. Talanta 64: 857–864.
Ghoneim, M. M., and M. A. El-Attar. 2008. Adsorptive stripping voltammetric determinationof antibiotic drug clarithromycin in bulk form, pharmaceutical formulation and humanurine. Chem. Anal.-Warsaw 53: 689–702.
Ghoneim, M. M., M. A. El-Attar, and S. A. Razeq. 2007. Voltammetric quantitation at themercury electrode of the anticholinergic drug flavoxate hydrochloride in bulk and in apharmaceutical formulation. Cent. Eur. J. Chem. 5: 496–507.
Ghoneim, M. M., H. S. El-Desoky, M. A. El-Ries, and A. M. Abd-Elaziz. 2008. Electrochemi-cal determination of muscle relaxant drug tetrazepam in bulk form, pharmaceutical formu-lation, and human serum. Chem. Pap. 62: 127–134.
Ghoneim, M. M., M. A. El-Reis, A. M. Hassanein, and A. M. Abd-Elaziz. 2006. Voltam-metric assay of the anthelmintic veterinary drug nitroxynil in bulk form and formulationat a mercury electrode. J. Pharm. Biomed. Anal. 41: 1268–1273.
Ghoneim, M. M., M. M. Mabrouk, and A. Tawfik. 2002. Direct determination of praziquan-tel in pharmaceutical formulations and human plasma by cathodic adsorptive strippingdifferential-pulse voltammetry. J. Pharm. Biomed. Anal. 30: 1311–1318.
Ghoneim, M. M., and A. Tawfik. 2004. Assay of anti-coagulant drug warfarin sodium inpharmaceutical formulation and human biological fluids by square-wave adsorptivecathodic stripping voltammetry. Anal. Chim. Acta 511: 63–69.
Golcu, A., B. Dogan, and S. A. Ozkan. 2005. Anodic voltammetric behavior and deter-mination of cefixime in pharmaceutical dosage forms and biological fluids. Talanta 67:703–712.
Golcu, A., and S. A. Ozkan. 2006. Electroanalytical determination of donepezil HCl in tabletsand human serum by differential pulse and osteryoung square wave voltammetry at a glassycarbon electrode. Pharmazie 61: 760–765.
Gomez Gonzalez, M. J., O. Dominguez Renedo, and M. J. Arcos Martinez. 2007. Speciationof antimony by adsorptive stripping voltammetry using pyrogallol. Talanta 71: 691–698.
Gonzalez, M. J., O. Dominguez Renedo, and M. J. Arcos Martinez. 2006. Speciation ofantimony by adsorptive stripping voltammetry using pyrogallol red. Electroanalysis 18:1159–1166.
Gosser, Jr., D. K., 1988. Cyclic Voltammetry: Simulation and Analysis of Reaction Mechanisms.New York: Wiley-VCH Pub.
Goyal, R. N., and S. Bishnoi. 2009. Simultaneous voltammetric determination of prednisoneand prednisolone in human body fluids. Talanta 79: 768–774.
Goyal, R. N., S. Chatterjee, and A. R. S. Rana. 2009. A single-wall carbon nanotubesmodified edge plane pyrolytic graphite sensor for determination of methylprednisolone inbiological fluids. Talanta 80: 586–592.
2690 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Goyal, R. N., V. K. Gupta, and S. Chatterjee. 2009. Fullerene-C60-modified edge planepyrolytic graphite electrode for the determination of dexamethasone in pharmaceuticalformulations and human biological fluids. Biosens. Bioelectron. 24: 1649–1654.
Goyal, R. N., V. K. Gupta, M. Oyama, and N. Bachheti. 2005. Differential pulse voltammetricdetermination of paracetamol at nanogold modified indium tin oxide electrode. Electrochem.Commun. 7: 803–807.
Goyal, R. N., V. K. Gupta, M. Oyama, and N. Bachheti. 2006. Differential pulse voltam-metric determination of atenolol in pharmaceutical formulations and urine using nanogoldmodified indium tin oxide electrode. Electrochem. Commun. 8: 65–70.
Goyal, R. N., V. K. Gupta, M. Oyama, and N. Bachheti. 2007. Gold nanoparticles modifiedindium tin oxide electrode for the simultaneous determination of dopamine and serotonin:Application in pharmaceutical formulations and biological fluids. Talanta 72: 976–983.
Goyal, R. N., M. Oyama, and S. P. Singh. 2007. Fast determination of salbutamol, abused byathletes for doping, in pharmaceuticals and human biological fluids by square wave voltam-metry. J. Electroanal. Chem. 611: 140–148.
Goyal, R. N., and S. P. Singh. 2006. Voltammetric determination of atenolol at C60-modifiedglassy carbon electrodes. Talanta 69: 932–937.
Goyal, R. N., A. Tyagi, N. Bachheti, and S. Bishna. 2008. Voltammetric determination ofbisoprolol fumarate in pharmaceutical formulations and urine using single-wall carbonnanotubes modified glassy carbon electrode. Electrochim. Acta 53: 2802–2808.
Greef, R., R. Peat, L. M. Peter, D. Pletcher, and J. Robinson. 1990. Instrumental Methods inElectrochemistry. New York: Ellis Harvood Limited.
Gungor, S. D. 2004. Electrooxidation of cetirizine dihydrochloride with a glassy carbonelectrode. Pharmazie 59: 929–931.
Habib, I. H. I., S. A. Weshahy, S. Toubar, and M. M. A. El-Alamin. 2008. Cathodic strippingvoltammetric determination of losartan in bulk and pharmaceutical products. Port. Electro-chim. Acta 26: 315–324.
Habib, I. H. I., and S. I. M. Zayed. 2005. Adsorptive stripping voltammetric determination ofambroxol. Pharmazie 60: 193–196.
Hamann, C. H., A. Hamnett, and W. Vielstich. 2007. Electrochemistry, 2nd completely revisedand updated ed. Weinheim: Wiley-VCH Pub.
Hammam, E. 2002. Determination of nitrofurantoin drug in pharmaceutical formulation andbiological fluids by square-wave cathodic adsorptive stripping voltammetry. J. Pharm.Biomed. Anal. 30: 651–659.
Hammam, E. 2004. Behavior and quantification studies of amiloride drug using cyclic andsquare-wave adsorptive stripping voltammetry at a mercury electrode. J. Pharm. Biomed.Anal. 34: 1109–1116.
Hammam, E. 2007. Determination of triamcinolone acetonide in pharmaceutical formulation andhuman serum by adsorptive cathodic stripping voltammetry. Chem. Anal.-Warsaw 52: 43–53.
Hammam, E., A. M. Beltagi, and M. M. Ghoneim. 2004. Voltammetric assay of rifampicineand isoniazid drugs, separately and combined in bulk, pharmaceutical formulations andhuman serum at a carbon paste electrode. Microchem. J. 77: 53–62.
Hammam, E., M. A. El-Attar, and A. M. Beltagi. 2006. Voltammetric studies on the antibioticdrug cefoperazone. Quantification and pharmacokinetic studies. J. Pharm. Biomed. Anal.42: 523–527.
Hammam, E., H. S. El-Desoky, K. Y. El-Baradie, and A. M. Beltagi. 2004. Three validatedstripping voltammetric procedures for determination of the anti-prostate cancer drug fluta-mide in tablets and human serum at a mercury electrode. Can. J. Chem. 82: 1386–1392.
Hammam, E., H. S. El-Desoky, A. Tawfik, and M. M. Ghoneim. 2004. Voltammetricbehavior and quantification of the anti-leukemia drug imatinib in bulk form, pharmaceuti-cal formulation, and human serum at a mercury electrode. Can. J. Chem. 82: 1203–1209.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2691
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Hart, J. P. 1990. Electroanalysis of Biologically Important Compounds. New York: EllisHorwood Pub.
Harvey, D. 2000. Modern Analytical Chemistry. Boston: McGrawHill.Hedge, R. N., and S. T. Nandibewoor. 2008. Electrochemical oxidation of pentoxifylline and
its analysis in pure and pharmaceutical formulations at a glassy carbon electrode. Anal.Lett. 41: 977–991.
Hernandez-Olmos, M. A., L. Agui, P. Yanez-Sedeno, and J. M. Pingarron. 2000. Analyticalvoltammetry in low-permitivity organic solvents using disk and cylindrical microelectrodes.Determination of thiram in ethyl acetate. Electrochim. Acta 46: 289–296.
Ibrahim, M. S., I. S. Shehatta, and M. R. Sultan. 2002. Cathodic adsorptive stripping voltam-metric determination of nalidixic acid in pharmaceuticals, human urine and serum. Talanta56: 471–479.
Jacques Barbosa, A. M., M. A. Goncalves Trindade, and V. S. Ferreira. 2006. Cathodic strip-ping voltammetry determination of ceftiofur antibiotic in formulations and bovine serum.Anal. Lett. 39: 1143–1158.
Jagner, D., and A. Graneli. 1976. Potentiometric stripping analysis.Anal. Chim. Acta 83: 19–26.Jain, R., A. Dwivedi, and R. Mishra. 2008. Voltammetric behavior of cefdinir in solubilized
system. J. Colloid Interface Sci. 318: 296–301.Jain, R., A. Dwivedi, and R. Mishra. 2009. Stripping voltammetric behaviour of toxic drug
nitrofurantoin. J. Hazard. Mater. 169: 667–672.Jain, R., V. K. Gupta, N. Jadon, and K. Radhapyari. 2010b. Adsorptive stripping voltam-
metric determination of pyridostigmine bromide in bulk, pharmaceutical formulationsand biological fluid. J. Electroanal. Chem. 648: 20–27.
Jain, R., N. Jadon, and K. Radhapyari. 2006. Determination of antihelminthic drug pyrantelpamoate in bulk and pharmaceutical formulations using electro-analytical methods. Talanta70: 383–386.
Jain, R., K. Radhapyari, and N. Jadon. 2007a. Adsorptive stripping voltammetric behaviorand determination of anticholinergic agent oxybutynin chloride on a mercury electrode.J. Colloid. Interf. Sci. 314: 572–577.
Jain, R., K. Radhapyari, and N. Jadon. 2007b. Electrochemical evaluation and determinationof cefdinir in dosage form and biological fluid at mercury electrode. J. Electrochem. Soc.154: 199–204.
Jain, R., K. Radhapyari, and N. Jadon. 2008. Electrochemical studies and determinationof gastroprokinetic drug mosapride citrate in bulk form and pharmaceutical dosage form.J. Electrochem. Soc. 155: F104–F109.
Jain, R., R. K. Yadav, and A. Dwivedi. 2010. Square-wave adsorptive stripping voltammetricbehaviour of entacapone at HMDE and its determination in the presence of surfactants.Colloid Surf. A 359: 25–30.
Jaiswa, L. P. V., V. S. Ijeri, and A. K. Srivastava. 2001. Voltammetric behavior of a-tocopheroland its determination using surfactantþ ethanolþwater and surfactantþ acetonitrileþwater mixed solvent systems. Anal. Chim. Acta 441: 201–206.
Jiang, X. F., and X. Q. Lin. 2006. Voltammetry of the interaction of metronidazole with DNAand its analytical applications. Bioelectrochem. 68: 206–212.
Jimenez Palacios, F. J.,M.CallejonMochon, J. C. Jimenez Sanchez, and J.HerreraCarranza. 2000.Electrochemical reduction of cefepime at the mercury electrode. Electroanalysis 12: 296–300.
Jin, W., and J. Wang. 1991. Investigations on adsorption stripping potentiometry: Part III.Theory of derivative adsorption potentiometry for a reversible reaction. Anal. Chim. Acta252: 59–64.
Kachoosangi, R. T., G. G. Wildgoose, and R. G. Compton. 2008. Adsorptive strippingvoltammetric determination of 4-hexylresorcinol in pharmaceutical products using multi-walled carbon nanotube based electrodes. Electroanalysis 20: 1714–1718.
2692 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Karimi-Maleh, H., A. A. Ensafi, and A. R. Allafchian. 2010. Fast and sensitive determinationof captopril by voltammetric method using ferrocenedicarboxylic acid modified carbonpaste electrode. J. Solid State Electrochem. 14: 9–15.
Kasim, E. A. 2002. Voltammetric behavior of the anti-inflammatory alkaloid colchicine at aglassy carbon electrode and a hanging mercury electrode and its determination at ppb levels.Anal. Lett. 35: 1987–2004.
Kasprzak, M., W. Ciesielshi, and S. Skyrzypek. 2005. Cathodic stripping voltammetry of2-thiouracils. Collect. Czech. Chem. Commun. 70: 188–197.
Kazemipour, M., M. Ansari, A. Mohammadi, H. Beitollahi, and R. J. Ahmadi. 2009. Use ofadsorptive square-wave anodic stripping voltammetry at carbon paste electrode for thedetermination of amlodipine besylate in pharmaceutical preparations. Anal. Chem. 64:
65–70.Kellner, R., J. M. Mermet, M. Otto, M. Valcarcel, and H. M. Widmer. 2004. Analytical Chem-istry: A Modern Approach to Analytical Science, 2nd Ed. Weinheim: Wiley-VCH Pub.
Khodari, M., H. Mansour, and G. A. Mersal. 1999. Cathodic stripping voltammetric behav-iour of nitrofurazone and its determination in pharmaceutical dosage form, urine and serumby linear sweep voltammetry. J. Pharm. Biomed. Anal. 20: 579–586.
Kissinger, P. T., and W. R. Heineman. 1996. Laboratory Techniques in ElectroanalyticalChemistry, 2nd ed. New York: Marcel Dekker.
Kissinger, P. T., and W. R. Heineman. 1983. Cyclic voltammetry. J. Chem. Educ. 60: 702–706.Komorsky-Lovric, S., and B. Nigovic. 2004. Identification of 5-aminosalicylic acid, ciproflox-acin and azithromycin by abrasive stripping voltammetry. J. Pharm. Biomed. Anal. 36: 81–89.
Komorsky-Lovric, S., and B. Nigovic. 2006. Electrochemical characterization of simvastatinby abrasive stripping and square-wave voltammetry. J. Electroanal. Chem. 593: 125–130.
Korany, M. A., I. I. Hewala, and K. M. Abdel-Hay. 2008. Determination of etofibrate, feno-fibrate, and atorvastatin in pharmaceutical preparations and plasma using differential pulsepolarographic and square wave voltammetric techniques. J. AOAC Int. 91: 1051–1058.
Korolczuk, M., and K. Tyszczuk. 2007a. Determination of folic acid by adsorptive strippingvoltammetry at a lead film electrode. Electroanalysis 19: 1959–1962.
Korolczuk, M., and K. Tyszczuk. 2007b. Adsorptive stripping voltammetry of trimethoprimat an in situ plated lead film electrode. Chem. Anal.-Warsaw 52: 1015–1024.
Koryta, J., J. Dvorak, and L. Kavan. 1993. Principles of Electrochemistry, 2nd Ed. New York:Wiley.
Kotkar, R. M., P. B. Desai, and A. K. Srivastava. 2007. Behavior of riboflavin on plaincarbon paste and aza macrocycles based chemically modified electrodes. Sens. Actuat. B124: 90–98.
Kotkar, R. M., and A. K. Srivastava. 2006. Voltammetric determination of para-aminobenzoic acid using carbon paste electrode modified with macrocyclic compounds.Sens. Actuat. B 119: 524–530.
Kowalczyk, P., A. Lozak, and Z. Fijalek. 2005. Determination of selenium in multicomponentpharmaceutical preparations. Chem. Anal.-Warsaw 50: 437–447.
Kumar, K. G., P. Augustine, R. Poduval, and S. John. 2006. Voltammetric studies of sparflox-acin and application to its determination in pharmaceuticals. Pharmazie 61: 291–292.
Lencastre, R. P., C. D. Matos, J. Garrido, F. Borges, and E. M. Garrido. 2006. Voltammetricquantification of fluoxetine: Application to quality control and quality assurance processes.J. Food Drug Anal. 14: 242–246.
Li, C. 2007. Voltammetric determination of ethinylestradiol at a carbon paste electrode in thepresence of cetyl pyridine bromine. Bioelectrochem. 70: 263–268.
Liu, X., P. A. Duckworth, and D. K. Y. Wong. 2010. Square wave voltammetry versuselectrochemical impedance spectroscopy as a rapid detection technique at electrochemicalimmunosensors. Biosens. Bioelectron. 25: 1467–1473.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2693
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Lourencao, B. C., R. A. Medeiros, R. C. Rocha-Filho, L. H. Mazo, and O. Fatibello-Filho.2009. Simultaneous voltammetric determination of paracetamol and caffeine in pharmaceu-tical formulations using a boron-doped diamond electrode. Talanta 78: 748–752.
Lozeno-Chaves, M. E., J. M. Palacios-Santonder, L. M. Cubillana-Aguilera, I. Naranjo-Rodrugnez, and J. L. Hidalgo-Hidaldo de Cisneros. 2006. Modified carbon-paste electrodesas sensors for the determination of 1,4-benzodiazepines: Application to the determination ofdiazepam and oxazepam in biological fluids. Sensor Actuat. B. 115: 575–578.
Lupu, S., A. Mucci, L. Pigani, R. Seeber, and C. Zanardi. 2002. Polythiophene derivativeconducting polymer modified electrodes and microelectrodes for determination of ascorbicacid. Effect of possible iInterferents. Electroanalysis 14: 519–525.
Ly, S. Y. 2006. Detection of dopamine in the pharmacy with a carbon nanotube pasteelectrode using voltammetry. Bioelectrochem. 68: 227–231.
Mazloum-Ardakoni, M., H. Beitollahi, M. A. S. Mosheni, A. Benvidi, H. Naemini, M.Nejati-Barzoki, and N. Taghavinia. 2010. Simultaneous determination of epinephrineand acetaminophen concentrations using a novel carbon paste electrode prepared with2,20-[1,2 butanediylbis (nitriloethylidyne)]-bis-hydroquinone and TiO2 nanoparticles.Colloid Surface B 76: 82–87.
Mielech-Lukasiewicz, K., H. Puzanowska-Torasiewicz, and A. Panuszko. 2008. Electrochemi-cal oxidation of phenothiazine derivatives at glassy carbon electrodes and their differentialpulse and square-wave voltammetric determination in pharmaceuticals. Anal. Lett. 41:789–805.
Mirceski, V., S. Komorsky-Lovric, and M. Lovric. 2007. In Square Wave Voltammetry Theoryand Application, ed. F. Scholz. Berlin: Springer-Verlag Pub.
Mirmamtaz, E., A. A. Ensafi, and H. Karimi-Maleh. 2008. Electrocatalytic determinationof 6-tioguanine at a p-aminophenol modified carbon paste electrode. Electroanalysis 20:
1973–1979.Modarres-Tehrani, Z., M. Askari, and J. Modifi. 2007. Electrochemical determination of lead
and cadmium traces in zinc oxide and magnesium stearate used as pharmaceutical products.Asian J. Chem. 19: 5391–5398.
Muralidharan, B., G. Gopu, C. Vedhi, and P. Manisankar. 2008. Voltammetric determinationof analgesics using a montmorillonite modified electrode. Appl. Clay. Sci. 42: 206–213.
Muralidharan, B., G. Gopu, C. Vedhi, and P. Manisankar. 2009. Determination of analgesicsin pharmaceutical formulations and urine samples using nano polypyrrole modified glassycarbon electrode. J. Appl. Electrochem. 39: 1177–1184.
Neves, M. M. P. S., H. P. A. Nouws, and C. Delerue-Matos. 2008. Direct electroanalyticaldetermination of fluvastatin in a pharmaceutical dosage form: Batch and flow analysis.Anal. Lett. 41: 2794–2804.
Niazi, A., and A. Yazdanipour. 2008. Determination of trace amounts of morphine in humanplasma by anodic adsorptive stripping differential pulse voltammetry. Chin. Chem. Lett. 19:465–468.
Nicholson, R. S. 1965. theory and application of cyclic voltammetry for measurement ofelectrode reaction kinetics. Anal. Chem. 37: 1351–1355.
Nigam, P., S. Mohan, S. Kundu, and R. Prakash. 2009. Trace analysis of cefotaxime at carbonpaste electrode modified with novel schiff base Zn(II) complex. Talanta 77: 1426–1431.
Nigovic, B. 2006. Electrochemical properties and square-wave voltammetric determination ofpravastatin. Anal. Bioanal. Chem. 384: 431–437.
Nigovic, B., S. Komorsky-Lovric, and D. Devcic. 2008. Rapid voltammetric identification anddetermination of simvastatin at trace levels in pharmaceuticals and biological fluid. Croat.Chem. Acta 81: 453–459.
Nigovic, B., and B. Simunic. 2003a. Determination of 5-aminosalicylic acid in pharmaceuticalformulation by differential pulse voltammetry. J. Pharm. Biomed. Anal. 31: 169–174.
2694 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Nigovic, B., and B. Simunic. 2003b. Voltammetric assay of azithromycin in pharmaceuticaldosage forms. J. Pharm. Biomed. Anal. 32: 197–202.
Norouzi, P., M. R. Ganjali, and B. Akbari-Adergani. 2006. Sub-second FFT Continuousstripping cyclic voltammetric technique as a novel method for pico-level monitoring ofimipramine at Au microelectrode in flowing solutions. Acta Chim. Slov. 53: 499–505.
Norouzi, P., M. R. Ganjali, and P. Daneshgar. 2007. A novel method for fast determination ofranitidine in its pharmaceutical formulations by fast continuous cyclic voltammetry. J.Pharmacol. Toxicol. Meth. 55: 289–296.
Norouzi, P., M. R. Ganjali, B. Larijani, and S. Karamdoust. 2008. A fast stripping continuouscyclic voltammetry method for determination of ultra trace amounts of nalidixic acid.Croat. Chim. Acta 81: 423–430.
Norouzi, P., M. R. Ganjali, and P. Matloobi. 2005. Sub-second adsorption for sub-nanomolarmonitoring of metoclopramide by fast stripping continuous cyclic voltammetry. Electro-chem. Commun. 7: 333–338.
Norouzi, P., M. R. Ganjali, M. Zare, and A. Mohammadi. 2007. Nano-level detection ofnaltrexone hydrochloride in its pharmaceutical preparation at Au microelectrode in flowingsolutions by fast fourier transforms continuous cyclic voltammetry as a novel detector. J.Pharm. Sci. 96: 2009–2017.
Nouws, H. P. A., C. Delerue-Matos, and A. Barros. 2006. Electrochemical determination ofcitalopram by adsorptive stripping voltammetry-determination in pharmaceutical products.Anal. Lett. 39: 1907–1915.
Nouws, H. P. A., C. Delerue-Matos, A. A. Barros, and J. A. Rodrigues. 2005. Electroanaly-tical study of the antidepressant sertraline. J. Pharm. Biomed. Anal. 39: 290–293.
Nouws, H. P. A., C. Delerue-Matos, A. A. Barros, and J. A. Rodrigues. 2006. Electroanaly-tical determination of paroxetine in pharmaceuticals. J. Pharm. Biomed. Anal. 42: 341–346.
Nouws, H. P.A., C. Delerue-Matos, A. A. Barros, J. A. Rodrigues, and A. Santos-Silva. 2005.Electroanalytical study of fluvoxamin. Anal. Bioanal. Chem. 382: 1662–1668.
Nouws, H. P. A., C. Delerue-Matos, A. A. Barros, J. A. Rodrigues, A. Santos-Silva, andF. Borges. 2007. Square-wave adsorptive-stripping voltammetric detection in the qualitycontrol of fluoxetine. Anal. Lett. 40: 1131–1146.
O’Dea, J. J., J. Osteryoung, and R. A. Osteryoung. 1981. Theory of square wave voltammetryfor kinetic systems. Anal. Chem. 53: 695–701.
Oliveira, R. T. S., G. R. Salazar-Banda, V. S. Ferreira, S. C. Oliveira, and L. A. Avaca. 2007.Electroanalytical determination of lidocaine in pharmaceutical preparations usingboron-doped diamond electrodes. Electroanalysis 19: 1189–1194.
Ozkan, S. A. 2009. Principles and techniques of electroanalytical stripping methods forpharmaceutically active compounds in dosage forms and biological samples. Curr. Pharm.Anal. 5: 127–143.
Ozkan, S. A., and B. Uslu. 2002. Electrochemical study of fluvastatin sodium: Application topharmaceutical dosage forms, human serum and simulated gastric juice. Anal. Bioanal.Chem. 372: 582–586.
Ozkan, S. A., B. Uslu, and H. Y. Aboul-Enein. 2003. Analysis of pharmaceuticals and biologi-cal fluids using modern electroanalytical techniques. Crit. Rev. Anal. Chem. 33: 155–181.
Ozkan, S. A., B. Uslu, and B. Dogan. 2006. Voltammetric analysis of the novel atypicalantipsychotic drug quetiapine in human serum and urine. Microchim. Acta 153: 27–35.
Ozkan, S. A., B. Uslu, and Z. Senturk. 2004. Electroanalytical characteristics of amisulprideand voltammetric determination of the drug in pharmaceuticals and biological media.Electroanalysis 16: 231–237.
Pacheco, W. F., P. A. M. Farias, and R. Q. Aucelio. 2005. Square-wave adsorptive strippingvoltammetry for the determination of cyclofenil after photochemical derivatization. Anal.Chim. Acta 549: 67–73.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2695
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Palaharn, S., T. Charoenraks, N. Wangfuengkanagul, K. Grudpan, and O. Chailapakul. 2003.Flow injection analysis of tetracycline in pharmaceutical formulation with pulsed ampero-metric detection. Anal. Chim. Acta 499: 191–197.
Parham, H., and B. Zargar. 2001. Determination of isosorbide dinitrate in arterial plasma,synthetic serum and pharmaceutical formulations by linear sweep voltammetry on a goldelectrode. Talanta 55: 255–262.
Parham, H., and B. Zargar. 2005. Square-wave voltammetric (SWV) determination of capto-pril in reconstituted serum and pharmaceutical formulations. Talanta 65: 776–780.
Pemberton, R. M., T. T. Mottram, and J. P. Hart. 2005. Development of a screen-printedcarbon electrochemical immunosensor for picomolar concentrations of estradiol in humanserum extracts. J. Biochem. Biophys. Methods. 63: 201–212.
Pournaghi-Azar, M. H., H. Razmi-Nerbin, and B. Hafezi. 2002. Amperometric determinationof ascorbic acid in real samples using an aluminum electrode, modified with nickel hexacya-noferrate films by simple electroless dipping method. Electroanalysis 14: 206–212.
Prasad, B. B., S. Srivastava, K. Tiwari, and P. S. Sharma. 2009. Ascorbic acid sensor based onmolecularly imprinted polymer-modified hanging mercury drop electrode. Mat. Sci. Eng.C-Mater. 29: 1082–1087.
Radi, A. 2005. Accumulation and trace measurement of chloroquine drug at DNA modifiedcarbon paste electrode. Talanta 65: 271–275.
Radi, A., N. Abd El-Ghany, and T. Wahdan. 2004. Voltammetric behaviour of rabeprazole ata glassy carbon electrode and its determination in tablet dosage form. Farmaco 59: 515–518.
Radi, A., M. A. El Ries, and S. Kandil. 2005. Spectroscopic and voltammetric studies ofPefloxacin bound to calf thymus double-stranded DNA. Anal. Bioanal. Chem. 381: 451–455.
Radi, A., M. S. El-Shahawi, and T. Elmogy. 2005. Differential pulse voltammetric determi-nation of the dopaminergic agonist bromocriptine at glassy carbon electrode. J. Pharm.Biomed. Anal. 37: 195–198.
Radi, A. E. 2006. Applications of Stripping Voltammetry at Carbon Paste and ChemicallyModified Carbon Paste Electrodes to Pharmaceutical Analysis. Curr. Pharm. Anal. 2: 1–8.
Radi, A. E., N. Abd-Elghany, and T. Wahdan. 2007. Electrochemical study of the antineo-plastic agent etoposide at carbon paste electrode and its determination in spiked humanserum by differential pulse voltammetry. Chem. Pharm. Bull. 55: 1379–1382.
Radovan, C., C. Cofan, and D. Cinghita. 2008. Simultaneous determination of acetamino-phen and ascorbic acid at an unmodified boron-doped diamond electrode by differentialpulse voltammetry in buffered media. Electroanalysis 20: 1346–1353.
Ramadan, A. A., H. Mandil, and M. A. Saleh. 2008. Pulse anodic stripping voltammetricdetermination of copper with an amoxicillin-nafion modified glassy carbon electrode. J.Applied Electrochem. 38: 1715–1720.
Raoof, J. B., R. Ojani, and H. Beitollahi. 2007. L-cysteine voltammetry at a carbon paste elec-trode bulk-modified with ferrocenedicarboxylic acid. Electroanalysis 19: 1822–1830.
Raoof, J. B., R. Ojani, H. Beitollahi, and R. Hossienzadeh. 2006. Electrocatalytic determi-nation of ascorbic acid at the surface of 2,7-bis(ferrocenyl ethyl)fluoren-9-one modifiedcarbon paste electrode. Electroanalysis 18: 1193–1201.
Raoof, J. B., R. Ojani, and F. Chekin. 2007. Electrochemical analysis of d-penicillamineusing a carbon paste electrode modified with ferrocene carboxylic acid. Electroanalysis19: 1883–1889.
Raoof, J. B., R. Ojani, and R. Hosseinzadeh. 2003. Electrocatalytic characteristics of a1-[4-(ferrocenyl ethynyl)phenyl]-1-ethanone modified carbon-paste electrode in theoxidation of ascorbic acid. Anal. Sci. 19: 1251–1258.
Reddy, T. M., M. Sreedhar, and S. J. Reddy. 2003. Electrochemical determination of sparflox-acin in pharmaceutical formulations and urine samples using a b-cyclodextrin modifiedcarbon paste electrode. Anal. Lett. 36: 1365–1379.
2696 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Renedo, O. D., and M. J. Arcos Martinez. 2007. A novel method for the anodic strippingvoltammetry determination of Sb(III) using silver nanoparticle-modified screen-printedelectrodes. Electrochem. Commun. 9: 820–826.
Rezaei, B., and Z. M. Zare. 2008b. Modified glassy carbon electrode with multiwall carbonnanotubes as a voltammetric sensor for determination of leucine in biological and pharma-ceutical samples. Anal. Lett. 41: 2267–2286.
Rezaei, B., and S. Z. M. Zare. 2008a. Modified glassy carbon electrode with multiwall carbonnanotubes as a voltammetric sensor for determination of noscapine in biological and phar-maceutical samples. Sens. Actuators B 134: 292–299.
Ribeiro, F. W. P., A. S. Cardoso, R. R. Portela, J. E. S. Lima, S. A. S. Machado, P. DeLima-Neto, D de Souza, and A. N. Correia. 2008. Electroanalytical determination of pro-methazine hydrochloride in pharmaceutical formulations on highly boron-doped diamondelectrodes using square-wave adsorptive voltammetry. Electroanalysis 20: 2031–2039.
Rieger, P. H. 1994. Electrochemistry, 2nd Ed. New York: Chapman & Hall Pub.Ries, M. A., A. A. Wassel, N. T. A. Ghani, and M. A. El-Shall. 2005. Electrochemical adsorp-tive behavior of some fluoroquinolones at carbon paste electrode. Anal. Sci. 21: 1249–1254.
Rievaj, M., P. Tomcik, Z. Janosikova, D. Bustin, and R. G. Compton. 2008. Determination oftrace Mn(II) in pharmaceutical diet supplements by cathodic stripping voltammetry on barecarbon paste electrode. Chem. Anal.-Warsaw 53: 153–161.
Rodriguez, J., J. J. Berzas, G. Castenada, and N. Rodriguez. 2005. Voltammetric determi-nation of imatinib (gleevec) and its main metabolite using square-wave and adsorptivestripping square-wave techniques in urine samples. Talanta 66: 202–209.
Roque Da Silva, A. M. S., J. C. Lima, M. T. Oliva Teles, and A. M. Oliveira-Brett. 1999. Elec-trochemical studies and square wave adsorptive stripping voltammetry of the antidepressantfluoxetine. Talanta 49: 611–617.
Sabry, S. M. 2007. Polarographic and voltammetric assays of sulfonamides as a-oxo-c-butyr-olactone arylhydrazones. Anal. Lett. 40: 233–256.
Sandulescu, R. V., S. M. Mirel, R. N. Oprean, and S. Lotrean. 2000. Comparative electro-chemical study of some phenothiazines with carbon paste, solid carbon paste and glass-likecarbon electrodes, Collection of Czechoslovak. Chem. Comm. 65: 1014–1018.
Santhosh, P., N. S. Kumar, M. Renukadevi, A. Y. Gopalon, T. Vasudevan, and K. P. Lee.2007. Enhanced electrochemical detection of ketorolac tromethamine at polypyrrolemodified glassy carbon electrode. Anal. Sci. 23: 475–478.
Santos, V. S., W. D. J. R. Santos, L. T. Kubota, and C. R. T. Tarley. 2009. Speciation ofSb(III) and Sb(V) in meglumine antimoniate pharmaceutical formulations by PSA usingcarbon nanotube electrode. J. Pharm. Biomed. Anal. 50: 151–157.
Sartori, E. R., R. A. Medeiros, R. C. Rocha-Filho, and O. Fatibello-Filho. 2009. Square-wavevoltammetric determination of acetylsalicylic acid in pharmaceutical formulations using aboron-doped diamond electrode without the need of previous alkaline hydrolysis step. J.Brazilian Chem. Soc. 20: 360–366.
Sawyer, D. T., A. Sobkowiak, and J. L. Robert Jr. 1995. Electrochemistry for chemists, 2nd ed.New York: Wiley-Interscience Pub.
Scholz, F., and B. Lange. 1990. High-performance abrasive stripping voltammetry. FreseniusJ. Anal. Chem. 338: 293–294.
Scholz, F., and B. Lange. 1992. Abrasive stripping voltammetry- an electrochemical solid statespectroscopy of wide applicability. Trac-Trends Anal. Chem. 11: 359–367.
Scholz, F., B. Lange, A. Jaworski, and J. Pelzer. 1991. Analysis of powdermixtures with the helpof abrasive stripping voltammetry and coulometry. Fresenius J. Anal. Chem. 340: 140–144.
Scholz, F., W. D. Muller, L. Nitschke, F. Rabi, L. Livanova, C. Fleischfresser, andC. Thierfelder. 1990. Fast and non-destructive identification of dental alloys by abrasivestripping voltammetry. Fresenius J. Anal. Chem. 338: 37–49.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2697
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Scholz, F., L. Nitschke, G. Henrion, and F. Damas-Chun. 1989. Abrasive strippingvoltammetry-the electrochemical spectroscopy for solid state: application for mineral analy-sis. Fresenius J. Anal. Chem. 335: 189–194.
Scholz, F., U. Schroder, and R. Gulaboski. 2005. Electrochemistry of immobilized particles anddroplets. Berlin: Springer Pub.
Seman, F. S., E. M. Pinto, E. T. G. Cavalheiro, and C. A. M. Brett. 2008. Agraphite-polyurethane composite electrode for the analysis of furosemide. Electroanalysis20: 2287–2293.
Seman, F. S., E. T. G. Cavalheiro, and C. M. A. Brett. 2009. Electrochemical behavior ofverapamil at graphite-polyurethane composite electrodes: Determination of release profilesin pharmaceutical samples. Anal. Lett. 42: 1119–1135.
Senturk, Z., S. A. Ozkan, and Y. Ozkan. 1998. Electroanalytical study of nifedipine usingactivated glassy carbon electrode. J. Pharm. Biomed. Anal. 16: 801–807.
Senturk, Z., S. A. Ozkan, Y. Ozkan, and H. Y. Aboul-Enein. 2000. Voltammetric investi-gation of oxidation of zuclopenthixol and application to its determination in dosage formsand in drug dissolution studies. J. Pharm. Biomed. Anal. 22: 315–323.
Shahrokhian, S., and B. Bozorgzadeh. 2006. Electrochemical oxidation of dopamine in thepresence of sulfhydryl compounds: Application to the square-wave voltammetric detectionof of penicillamine and cysteine. Electrochim. Acta 51: 4271–4276.
Shahrokhian, S., and L. Fotouhi. 2007. Carbon paste electrode incorporating multi-walledcarbon nanotube=cobalt salophen for sensitive voltammetric determination of tryptophan.Sensor Actuators B 123: 942–949.
Shahrokhian, S., and M. Ghalkhania. 2008. Voltammetric determination of methimazoleusing a carbon paste electrode modified with a schiff base complex of cobalt. Electroanalysis20: 1061–1066.
Shahrokhian, S., M. Karimi, and H. Khajehsharifi. 2005. Carbon-paste electrode modifiedwith cobalt-5-nitrolsalophen as a sensitive voltammetric sensor for detection of captopril.Sensor Actuators B 109: 278–284.
Shamsipur, M., and K. Farhadi. 2000. Electrochemical behavior and determination ofketoconazole from pharmaceutical preparations. Electroanalysis 12: 429–433.
Siangproh, W., W. N. Wangfuengkanagul, and O. Chailapakul. 2003. Electrochemicaloxidation of tiopronin at diamond film electrodes and its determination by amperometricflow injection analysis. Anal. Chim. Acta 499: 183–189.
Skrzypek, S., W. Ciesielski, A. Sokołowski, S. Yilmaz, and D. Kazmierczak. 2005. Squarewave adsorptive stripping voltammetric determination of famotidine in urine. Talanta 66:1146–1151.
Smyth, M. R., and J. G. Vos. 1992. Analytical Voltammetry. Vol. XXVII, Amsterdam:Elsevier Science Pub.
Solangi, A. R., M. Y. Khuhawar, and M. I. Bhanger. 2005. Adsorptive stripping voltammetricdetermination of fluoroquinolones in pharmaceuticals. J. Food Drug Anal. 13: 201–204.
Song, J. F., P. He, and W. Guo. 2002. Study on the polarographic catalytic wave of vitamin pin the presence of persulfate and its application. Anal. Biochem. 304: 212–219.
Sun, D., H. Wang, and K. Wu. 2006. Electrochemical determination of 10-hydroxycampt-othecin using a multi-wall carbon nanotube-modified electrode. Microchim. Acta 152:
255–260.Sun, N., W. M. Mo, Z. L. Shen, and B. X. Hu. 2005. Adsorptive stripping voltammetric tech-
nique for the rapid determination of tobramycin on the hanging mercury electrode. J.Pharm. Biomed. Anal. 38: 256–262.
Suryanarayanan, V., Y. Zhang, S. Yoshihara, and T. Shirakashi. 2005. Voltammetric assayof naproxen in pharmaceutical formulations using boron-doped diamond electrode.Electroanalysis 17: 925–932.
2698 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Suslu, I., and S. Altinoz. 2005. Electrochemical characteristics of zafirlukast and its determi-nation in pharmaceutical formulations by voltammetric methods. J. Pharm. Biomed. Anal.39: 535–542.
Suslu, I., and S. Altınoz. 2008. Electrochemical behavior of quinapril and its determination inpharmaceutical formulations by square-wave voltammetry at a mercury electrode. Pharma-zie 63: 428–433.
Suslu, I., N. Ozaltın, and S. Altınoz. 2009. Square-wave adsorptive stripping voltammetricdetermination of candesartan cilexetil in pharmaceutical formulations. J. Appl. Electrochem.39: 1535–1543.
Suw, Y. L. 2008. Voltammetric analysis of DL-a-tocopherol with a paste electrode. J. Sci.Food. Agr. 88: 1272–1276.
Tapsoba, I., J. E. Belgaied, and K. Boujlel. 2005. Voltammetric assay of guaifenesin inpharmaceutical formulation. J. Pharm. Biomed. Anal. 38: 162–165.
Teixeira, M. F. S., L. H. Marcolino, Jr., O. Fatibello-Filho, E. R. Dockal, and E. T. G.Cavalheiro. 2004. Voltammetric determination of dipyrone using an n,n’ ethylenebis(salicy-lideneaminato) oxovanadium (IV) modified carbon-paste electrode. J. Brazilian Chem. Soc.15: 803–808.
Teixeira, M. F. S., G. Marino, E. R. Dockal, and E. T. G. Cavaheiro. 2004. Voltammetricdetermination of pyridoxine (Vitamin B6) at a carbon paste electrode modified with vanadyl(IV)–Salen complex. Anal. Chim. Acta. 508: 79–85.
Teixeira, M. F. S., A. Segnini, F. C. Moraes, L. H. Marcolino-Junior, O. Fatibello-Filho, andE. T. G. Cavalheiro. 2003. Determination of vitamin B6 (pyridoxine) in pharmaceuticalpreparations by cyclic voltammetry at a copper(II) hexacyanoferrate(III) modified carbonpaste electrode. J. Brazilian Chem. Soc. 14: 316–321.
Toito Suarez, W., L. H. Marcolino, Jr., and O. Fatibello-Filho. 2006. Voltammetric determi-nation of N-acetylcysteine using a carbon paste electrode modified with copper(II) hexacya-noferrate(III). Microchem. J. 82: 163–167.
Toral, M. I., M. Paine, P. Leyton, and P. Richter. 2004. Determination of attapulgite andnifuroxazide in pharmaceutical formulations by sequential digital derivative spectrophoto-metry. J. AOAC Int. 87: 1323–1328.
Torriero, A. A. J., J. M. Luco, L. Sereno, and J. Raba. 2004. Voltammetric determination ofsalicylic acid in pharmaceuticals formulations of acetylsalicylic acid. Talanta 62: 247–254.
Torriero, A. A. J., J. J. T. Ruiz-Diaz, E. Salinas, E. J. Marceusky, M. I. Soha, and J.Raba. 2006. Enzymatic rotating biosensor for ciprofloxacin determination. Talanta 69:
691–699.Trindade, M. A. G., G. M. da Silva, and V. S. Ferreira. 2005. Determination of moxifloxacin intablets and human urine by square-wave adsorptive voltammetry.Microchem. J. 81: 209–216.
Turan, S., Z. Durmus, and E. Kilic. 2009. Electrochemical behavior of ornidazole and itsadsorptive stripping determination in pharmaceuticals. Curr. Pharm. Anal. 5: 416–423.
Turhan, E., and B. Uslu. 2008. Electroanalytical determination of opipramol in pharmaceuti-cal preparations and biological fluids. Anal. Lett. 41: 2013–2032.
Turkoz, E., and N. Onar. 2007. Determination of ticlopidine in pharmaceutical products.Anal. Lett. 40: 2231–2240.
Tyszczuk, K. 2008. Application of an in situ plated lead film electrode to the analysis oftestosterone by adsorptive stripping voltammetry. Anal. Bioanal. Chem. 390: 1951–1956.
Tyszczuk, K. 2009. Sensitive voltammetric determination of rutin at an in situ plated lead filmelectrode. J. Pharm. Biomed. Anal. 49: 558–561.
Tyszczuk, K., and M. Korolczuk. 2009a. In-Situ plated lead film electrode for determinationof glipizide in pharmaceutical formulation and human urine. Chem. Anal. 54: 31–41.
Tyszczuk, K., and M. Korolczuk. 2009b. New protocol for determination of rifampicine byadsorptive stripping voltammetry. Electroanalysis 21: 101–106.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2699
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Tyszczuk, K., and M. Korolczuk. 2010. Voltammetric method for the determination ofsildenafil citrate (Viagra) in pure form and in pharmaceutical formulations. Bioelectrochem.78: 113–117.
Uslu, B. 2002. Voltammetric analysis of alfuzosin HCl in pharmaceuticals, human serum andsimulated gastric juice. Electroanalysis. 14: 866–870.
Uslu, B., B. T. Demircigil, S. A. Ozkan, Z. Senturk, and H. Y. Aboul-Enein. 2001. Simul-taneous voltammetric determination of melatonin and pyridoxine HCl in pharmaceuticaldosage forms. Pharmazie 56: 938–942.
Uslu, B., B. Dogan, S. A. Ozkan, and H. Y. Aboul-Enein. 2005a. Electrochemical behavior ofvardenafil on glassy carbon electrode: Determination in tablets and human serum. Anal.Chim. Acta. 552: 127–134.
Uslu, B., B. Dogan, S. A. Ozkan, and H. Y. Aboul-Enein. 2005b. Voltammetric investigationand determination of mefloquine. Electroanalysis 17: 1563–1570.
Uslu, B., B. Dogan Topal, and S. A. Ozkan. 2005. Electrochemical studies of ganciclovir atglassy carbon electrodes and its direct determination in serum and pharmaceutics by squarewave and differential pulse voltammetry. Anal. Chim. Acta. 537: 307–313.
Uslu, B., B. Dogan-Topal, and S. A. Ozkan. 2008. Electroanalytical investigation and deter-mination of pefloxacin in pharmaceuticals and serum at boron-doped diamond and glassycarbon electrodes. Talanta 74: 1191–1200.
Uslu, B., and S. A. Ozkan. 2003. Electroanalytical characteristics of piribedil and its differen-tial pulse and square wave voltammetric determination in pharmaceuticals and humanserum. J. Pharm. Biomed. Anal. 31: 481–489.
Uslu, B., and S. A. Ozkan. 2004. Anodic voltammetry of abacavir and its determination inpharmaceuticals and biological fluids. Electrochim. Acta 49: 4321–4329.
Uslu, B., and S. A. Ozkan. 2007a. Electroanalytical application of carbon based electrodes tothe pharmaceuticals. Anal. Lett. 40: 817–853.
Uslu, B., and S. A. Ozkan. 2007b. Solid electrodes in electroanalytical chemistry: Presentapplications and prospects for high-throughput screening of drug compounds. Comb. Chem.High Through. Screen. 10: 495–513.
Uslu, B., S. A. Ozkan, and H. Y. Aboul-Enein. 2002. Electrochemical study of S-adenosyl-L-methionine and its differential pulse and square-wave voltammetric determination. Electro-analysis 14: 736–740.
Uslu, B., S. A. Ozkan, and Z. Senturk. 2006. Electrooxidation of the antiviral drug valacyclo-vir and its square-wave and differential pulse voltammetric determination in pharmaceuti-cals and human biological fluids. Anal. Chim. Acta. 555: 341–347.
Uslu, B., S. Yılmaz, and S. A. Ozkan. 2001. Determination of olsalazine sodium in pharma-ceuticals by differential pulse voltammetry. Pharmazie 56: 629–632.
Vacek, J., Z. Andrysik, L. Trnkova, and R. Kizek. 2004. Determination of azidothymidine–An antiproliferative and virostatic drug by square-wave voltammetry. Electroanalysis 16:224–230.
Vasjari, M., A. Merkoci, J. P. Hart, and S. Alegret. 2005. Amino acid determination usingscreen-printed electrochemical sensors. Microchim. Acta 150: 233–238.
Vela, M. H., M. B. Quinaz Garcia, and M. C. B. S. M. Montenegro. 2001. Electrochemicalbehaviour of sertraline at a hanging mercury drop electrode and its determination inpharmaceutical products. Anal. Bioanal. Chem. 369: 563–566.
Wang, C., X. Shao, Q. Liu, Q. Qu, G. Yang, and X. J. Hu. 2006. Differential pulse voltam-metric determination of nimesulide in pharmaceutical formulation and human serum atglassy carbon electrode modified by cysteic acid=CNTs based on electrochemical oxidationof l-cysteine. J. Pharm. Biomed. Anal. 42: 237–244.
Wang, J. 1988. Electroanalytical Techniques in Clinical Chemistry and Laboratory Medicine.New York: Wiley-VCH Pub.
2700 B. USLU AND S. A. OZKAN
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Wang, J. 2006. Electroanalytical Chemistry. 3rd ed. New Jersey: Wiley-VCH Pub.Wang, J., B. Tian, J. Wang, J. Lu, C. Olsen, C. Yarnitzky, K. Olsen, D. Hammerstrom, andW. Bennett. 1999. Stripping analysis into the 21st century: Faster, smaller, cheaper, simplerand better. Anal. Chim. Acta 385: 429–435.
Wang, F., Y. Wu, J. Liu, and B. Ye. 2009. DNA Langmuir–Blodgett modified glassy carbonelectrode as voltammetric sensor for determinate of methotrexate. Electrochim. Acta 54:1408–1413.
Wang, S. F., F. Xie, R. F. Hu, and H. C. Cai. 2006. The determination of nonelectroactiveanticancer drug 6-thioguanine on DNA-modified gold electrode. Anal. Lett. 39: 1041–1052.
Wangfuengkanagul, N., and O. Chailapakul. 2002. Electrochemical analysis of acetamino-phen using a boron-doped diamond thin film electrode applied to flow injection system.J. Pharm. Biomed. Anal. 28: 841–847.
Winter, E., L. Codognoto, and S. Rath. 2007. Electrochemical behavior of dopamine at amercury electrode in the presence of citrate: Analytical applications. Anal. Lett. 40:1197–1208.
Wu, S. H., J. J. Sun, D. F. Zhang, Z. B. Lin, F. H. Nie, H. Y. Qiu, and G. N. Chen.2008. Nanomolar detection of rutin based on adsorptive stripping analysis at single-sidedheated graphite cylindrical electrodes with direct current heating. Electrochim. Acta 53:
6596–6601.Yang, G. T., J. J. Xu, K. Wang, and H. Y. Chen. 2006. Electrocatalytic oxidation of dopamineand ascorbic acid on carbon paste electrode modified with nanosized cobalt phthalocyanineparticles: simultaneous determination in the presence of CTAB. Electroanalysis 18: 282–290.
Yang, G., C. Wang, R. Zhang, C. Wang, Q. Qu, and X. Hu. 2008. Poly(amidosulfonic acid)modified glassy carbon electrode for determination of isoniazid in pharmaceuticals. Bioelec-trochem. 73: 37–42.
Yardım, Y., E. Keskin, A. Levent, M. Ozsoz, and Z. Senturk. 2010. Voltammetric studies onthe potent carcinogen, 7,12-dimethylbenz[a]anthracene: Adsorptive stripping voltammetricdetermination in bulk aqueous forms and human urine samples and detection of DNAinteraction on pencil graphite electrode. Talanta 80: 1347–1355.
Yardımcı, C., and N. Ozaltın. 2001. Electrochemical studies and differential pulse polaro-graphic analysis of lansoprazole in pharmaceuticals. Analyst 126: 361–366.
Yardımcı, C., and N. Ozaltın. 2004. Electrochemical studies and square-wave voltammetricdetermination of fenofibrate in pharmaceutical formulations. Anal. Bioanal. Chem. 378:495–498.
Yılmaz, S., B. Uslu, and S. A. Ozkan. 2001. Anodic oxidation of etodolac and its square waveand differential pulse voltammetric determination in pharmaceuticals and human serum.Talanta 54: 351–360.
Yılmaz, S. 2009. Adsorptive stripping voltammetric determination of zopiclone in tabletdosage forms and human urine. Colloid Surf. B 71: 79–83.
Zayed, S. I. M., and I. H. I. Habib. 2005. Adsorptive stripping voltammetric determination oftriprolidine hydrochloride in pharmaceutical tablets. Farmaco 60: 621–625.
Zayed, S. I. M., and Y. M. Issa. 2009. Cathodic adsorptive stripping voltammetry ofdrotaverine hydrochloride and its determination in tablets and human urine by differentialpulse voltammetry. Bioelectrochem. 75: 9–12.
Zhang, X. H., and S. F. Wang. 2005. Determination of ethamsylate in the presence of catecho-lamines using 4-amino-2-mercaptopyrimidine self-assembled monolayer gold electrode.Sens. Actuator B 104: 29–34.
Zhang, H., L. Xu, and J. Zheng. 2007. Anodic voltammetric behavior of resveratrol and itselectroanalytical determination in pharmaceutical dosage form and urine. Talanta 71: 19–24.
Zhao, G. H., Y. Qi, and Y. Tian. 2006. Simultaneous and direct determination of tryptophanand tyrosine at boron-doped diamond electrode. Electroanalysis 18: 830–834.
ELECTROANALYTICAL METHODS FOR PHARMACEUTICALS 2701
Dow
nloa
ded
by [
Ank
ara
Uni
vers
itesi
] at
23:
05 0
1 Ja
nuar
y 20
12
Zhou, J., G. C. Gerhardt, A. Baranski, and R. Cassidy. 1999. Capillary electrophoresis ofsome tetracycline antibiotics coupled with reductive fast cyclic voltammetric detection. J.Chromatogr. A 839: 193–201.
Zhuang, Q., J. Chen, J. Chen, and X. Lin. 2008. Electrocatalytical properties of bergenin on amulti-wall carbon nanotubes modified carbon paste electrode and its determination intablets. Sens. Actuator B 128: 500–506.
Ziyatdinova, G. K., G. K. Budnikov, and V. I. J. Pogoreltsev. 2006. Determination of captoprilin pharmaceutical forms by stripping voltammetry. Anal. Chem. 61: 798–800.
Zoski, C. G. 2007. Handbook of Electrochemistry, 1st ed. Amsterdam: Elsevier Pub.
