Electrocatalytic oxidation of glutathione at carbon paste electrode modified with 2,7-bis (ferrocenyl ethyl) fluoren-9-one: application as a voltammetric sensor

Abstract

Electrooxidation of glutathione (GSH) was studied at the surface of 2,7-bis (ferrocenyl ethyl) fluoren-9-one modified carbon paste electrode (2,7-BFEFMCPE). Cyclic voltammetry (CV), double potential-step chronoamperometry, and differential pulse voltammetry (DPV) were used to investigate the suitability of this ferrocene derivative as a mediator for the electrocatalytic oxidation of GSH in aqueous solutions with various pH. Results showed that pH 7.00 is the most suitable pH for this purpose. At the optimum pH, the oxidation of GSH at the surface of this modified electrode occurs at a potential of about 0.410 V versus Ag|AgCl|KCl sat . The kinetic parameters such as electron transfer coefficient, a = 0.61, and rate constant for the chemical reaction between GSH and redox site in 2,7-BFEFMCPE, k h = 1.73 9 10 3 cm 3 mol -1 s -1 , were also determined using electrochemical approaches. Also, the apparent diffusion coefficient, D app , for GSH was found to be 5.0 9 10 -5 cm 2 s -1 in aqueous buffered solution. The electrocatalytic oxidation peak current of GSH showed a linear dependence on the glutathione concentration, and linear calibration curves were obtained in the ranges of 5.2 9 10 -5 M to 4.1 9 10 -3 M and 9.2 9 10 -7 M to 1.1 9 10 -5 M with cyclic voltammetry and differential pulse voltammetry methods, respectively. The detection limits (3r) were determined as 1.4 9 10 -5 M and 5.1 9 10 -7 M for the CV and DPV methods, respectively. This method was also examined as a selective, simple, and precise new method for voltammetric determination of GSH in real sample such as hemolysed erythrocyte.

Voltammetric sensor for D-penicillamine determination based on its electrocatalytic oxidation at the surface of ferrocenes modified carbon paste electrodes

“…17,29 Their cyclic voltammograms (figure 1a and b) exhibit one anodic and cathodic peak corresponding with redox system Fc/Fc + , which show a quasi-reversible behaviour in an aqueous medium. The cyclic voltammogram of bare CPE in pure supporting electrolyte shows no anodic or cathodic peaks (figure 1c).…”

“…17 Therefore, pH optimization of the solution seems to be necessary in order to obtain the electrocatalytic oxidation of D-PA. Thus, we studied the electrochemical behaviour of D-PA in 0⋅1 M phosphate buffered solutions with various pH values (2⋅00 < pH < 10⋅00) at the surface of FCCPE and 2,7-BFEFMCPE by cyclic voltammetry ( figure 3A).…”

“…One of the most important effects of any mediator is a reduction of the overpotential required for electrochemical reaction and increase of the sensitivity and selectivity of method. 15 Chemically modified electrodes based on reversible redox mediators such as ferrocenes, [16][17][18][19][20][21][22] hydroquinones 23 and catechols 24,25 have been widely used for the electrocatalytic detection of some sulfur-containing amino acids.…”

A Differential Pulse Voltammetric Sensor for Determination of Glutathione in Real Samples Using a Trichloro(terpyridine)ruthenium(III)/Multiwall Carbon Nanotubes Modified Paste Electrode

“…However, most of these methods suffer from difficulties of sample preparation, the necessity for derivatization, or lack of sufficient sensitivity, all of which limit their utility. Compared with the other techniques, electrochemical methods [15][16][17][18] have shown remarkable advantages in the analysis of different compounds in real samples. These advantages are mainly due to the simplicity, low cost, and relatively short analysis times of these compounds as compared to the chromatography methods [19][20][21][22][23][24][25][26].…”

Application of &#946;-cyclodextrin/MnFe2O4 magnetic nanoparticles as a catalyst for fast chemiluminescence determination of glutathione in human blood using luminol-diperiodatoargentate(III) System

“…Measurement of free GSH in the blood samples is essential to estimate the detoxification and redox status of cells because it has the protective role against oxidative and free radical-mediated radiation cell injury. 3 A number of methods used for the determination of GSH have been reported including enzymatic, 4 spectrophotometric, [5][6][7] high performance liquid chromatography (HPLC), 8,9 electrochemical methods [10][11][12][13][14][15][16][17][18] and chemiluminescence. [19][20][21][22][23] The spectrophotometric methods are simple but not sufficiently sensitive.…”