Voltammetric measurement of trace amount of glutathione using multiwall carbon nanotubes as a sensor and chlorpromazine as a mediator

Journal of Solid State Electrochemistry (Impact Factor: 2.45). 08/2010; 14(8):1415-1423. DOI: 10.1007/s10008-009-0978-z


In this work, we propose chlorpromazine as a new mediator for the rapid, sensitive, and highly selective voltammetric determination
of glutathione (GSH) using multiwall carbon nanotubes paste electrode (MWCNTPE). The experimental results showed that the
carbon nanotubes paste electrode has a highly electrocatalytic activity for the oxidation of GSH in the presence of chlorpromazine
as a mediator. Cyclic voltammetry, double potential step chronoamperometry, and differential pulse voltammetry (DPV) are used
to investigate the suitability of chlorpromazine at the surface of MWCNTPE as a mediator for the electrocatalytic oxidation
of GSH in aqueous solutions. It is shown that chlorpromazine can catalyze the oxidation of GSH in an aqueous buffer solution
to produce a sharp oxidation peak current at about +0.70 versus Ag/AgCl as a reference electrode. Kinetic parameters such
as electron transfer coefficient and catalytic reaction rate constant, k/h, are also determined. Using DPV and under the optimum
conditions at pH 4.0, the electrocatalytic oxidation peak current of GSH shows a linear dependence on GSH concentration in
the GSH concentration range of 0.3 to 18.3µM. The detection limit (3σ) is determined to be 0.16µM. The relative standard deviation for 1.5 and 5.0µM GSH are found to be 3.7% and 2.5%, respectively.
The proposed method may, thus, also be used as a novel, selective, simple, and precise method for the voltammetric determination
of GSH in such real samples as hemolyzed erythrocyte.

KeywordsChlorpromazine-Electrocatalysis-Glutathione determination-Voltammetric methods

14 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work, p-aminophenol-multiwall carbon nanotubes-TiO(2) is proposed as a sensor for the rapid, sensitive, and highly selective voltammetric determination of penicillamine (PA) in the presence of uric acid (UA). The electrochemical behavior of the compounds at this modified electrode was studied by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The results indicated that the chemically modified electrode exhibits efficient electrocatalytic activity in the oxidation of PA which occurs at a potential of about 530 mV, less positive than that for the unmodified carbon nanotubes paste electrode at pH 6.0. Peak potentials of PA and UA were separated with a difference of 215 mV using DPV. These conditions were sufficient to allow for the determination of PA and UA, both individually and simultaneously. At pH 6.0, the catalytic peak currents were linearly dependent on PA and UA concentrations in the ranges 0.4-200 micromol L(-1) PA and 3.0-1000 micromol L(-1) UA. Detection limits for PA and UA were 0.1 and 1.1 micromol L(-1), respectively. The RSD% for 1.2 and 1.5 micromol L(-1) PA were 1.6% and 2.1%, respectively, whereas they were 1.5% and 1.1% for 15.0 and 30.0 micromol L(-1) UA, respectively. Finally, the sensor was examined as a selective, simple, and precise new electrochemical sensor for the determination of PA in real samples in the presence of UA in drugs and urine.
    Colloids and surfaces B: Biointerfaces 11/2010; 81(1):42-9. DOI:10.1016/j.colsurfb.2010.06.020 · 4.15 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Determination of cysteamine and tryptophan is described by electrochemical methods using p-aminophenol-multiwall carbon nanotubes paste electrode. Cysteamine and tryptophan in mixture can each be measured independently from each other with a potential difference of 600 mV. The results showed that the electrocatalytic currents increased linearly with cysteamine and tryptophan concentrations over the ranges 0.5–300 µmol L−1 and 10.0–650 µmol L−1, respectively. The detection limits for cysteamine and tryptophan are found to be 0.14 and 5.9 µmol L−1, respectively. The proposed method is successfully employed for the determination of cysteamine in both capsule and urine samples.
    Electroanalysis 11/2010; 22(21):2558 - 2568. DOI:10.1002/elan.201000270 · 2.14 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This work describes a novel type of working electrode for use in voltammetry methods. Graphene is ideally suited for implementation in electrochemical applications due to its reported large electrical conductivity, large surface area, unique heterogeneous electron transfer rate, and low production costs. This paper presents a method for the construction of graphene paste electrode (GPE) from graphene. The GPE is not needed to be modified, because the surface of graphene is functionalized. Direct electrochemical detection of drug is of high importance in analytical chemistry. Here, the GPE was successfully used for the determination of chlorpromazine.
    Electrochemistry Communications 04/2011; 13(4):366-369. DOI:10.1016/j.elecom.2011.01.027 · 4.85 Impact Factor
Show more