Novel sensor based on carbon paste/Nafion® modified with gold nanoparticles for the determination of glutathione

Abstract

Several problems for the direct electrochemical oxidation of reduced glutathione (GSH) challenge the usage of electroanalytical techniques for its determination. In this work, the electrochemical oxidation of GSH catalyzed by gold nanoparticles electrodeposited on Nafion modified carbon paste electrode in 0.04 mol L(-1) universal buffer solution (pH 7.4) is proved successful. The effect of various experimental parameters including pH, scan rate and stability on the voltammetric response of GSH was investigated. At the optimum conditions, the concentration of GSH was determined using differential pulse voltammetry (DPV) in two concentration ranges: 0.1 × 10(-7) to 1.6 × 10(-5) mol L(-1) and 2.0 × 10(-5) to 2.0 × 10(-4) mol L(-1) with correlation coefficients 0.9988, 0.9949 and the limit of detections (LOD) are 3.9 × 10(-9) mol L(-1) and 8.2 × 10(-8) mol L(-1), respectively, which confirmed the sensitivity of the electrode. The high sensitivity, wide linear range, good stability and reproducibility, and the minimal surface fouling make this modified electrode useful for the determination of spiked GSH in urine samples and in tablet with excellent recovery results obtained.

Glassy carbon electrode modified with 7,7,8,8-tetracyanoquinodimethane and graphene oxide triggered a synergistic effect: Low-potential amperometric detection of reduced glutathione

“…Surfaceimmobilized TCNQ also undergoes a remarkable 'inert zone' in which no faradaic reaction yields, suggesting a typical solid-solid phase transformation in terms of nucleation and growth (Gómez and Rodríguez-Amaro, 2006). Further, with the increasing cycle, the voltammetric peak heights decay due to the dissolution of TCNQ into the solution (Bond et al, 1998). The results obtained are in good agreement with previous reports (Gómez and Rodríguez-Amaro, 2006;Bond et al, 1998).…”

“…Further, with the increasing cycle, the voltammetric peak heights decay due to the dissolution of TCNQ into the solution (Bond et al, 1998). The results obtained are in good agreement with previous reports (Gómez and Rodríguez-Amaro, 2006;Bond et al, 1998). The electrochemical behavior of immobilized TCNQ on the surface of GO or rGO was also studied, as shown in Fig.…”

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“…7) at scan rate = 10 mV s [36][37][38] were calculated and they were found to be 2.82 x10 -9 mol L −1 and 9.40 x 10 -9 mol L −1 , respectively. Intra-day and inter-day (n = 5) relative standard deviations of samples concentrations (10,60, and 100 µmol L -1 ) of EN were calculated to be 0.02 and 0.03, respectively.…”

A miniaturized electrochemical assay for homocysteine using screen-printed electrodes with cytochrome c anchored gold nanoparticles

“…6, due to the strong reducing property of AsA converting the ferric heme group of cyt c (Fe 3+ ) into the ferrous form (Fe 2+ ) and subsequently cyt c loses its activity for the oxidation of HcySH. In order to eliminate the interference due to AsA, the biosensing element (cyt c-GNP-SPE) was covered with a Nafion membrane 52 by placing the Nafion resin solution (5% solution (w/w) diluted to a final concentration of 1% (w/w) using ethanol) onto the substrate and drying at room temperature, which resulted in a thin, porous and negatively charged membrane. After Nafion coating, the interference with AsA was eliminated, as indicated by the enhanced oxidation current as shown in Fig.…”