Voltammetric determination of cysteine at a graphite electrode modified with gold nanoparticles

Abstract

The electrochemical behaviour of cysteine (Cys) at a graphite electrode modified with gold nanoparticles (GAu nano electrode) was studied by cyclic voltammetry. It was found that the graphite electrode-Au nanoparticles show an electrocatalytic activity towards the oxidation of Cys in 0.1 M NaOH. At 0.05 V, there is an "inverse" maximum in the cathodic voltammogram of Cys. Using a G-Au nano electrode, the dependence of the peak current of the "inverse" maximum on Cys concentration was linear in the range from 1 to 14 pM, and the detection limit was 0.6 pM. The proposed analytical method is simple, rapid and sensitive.

A sensitive chemiluminescence method for the determination of cysteine based on silver nanoclusters

“…Due to its fundamental importance in biological systems, detection of cysteine is of great importance. In the past years, many techniques for the determination of cysteine, such as spectrophotometry [3,4], fluorimetry [5][6][7] and electrochemical methods [8][9][10] have been reported. Although most of these methods have the advantage of being sensitive and specific, they are either cost-ineffective, complicated or time-consuming.…”

Evaluation of a Graphite-Polyurethane Composite Electrode Modified with Copper Nanoparticles as an Amperometric Flow Detector in a Wall-Jet System for the Determination of Cysteine

“…Isabela A. Mattioli, a Letícia F. L. Schildt, a Priscila Cervini, a Thalita R. Saciloto a and Éder T. G. Cavalheiro * ,a high sensitivity, easiness of sample preparation, low cost and faster analysis. 11 Regarding Cys determination using amperometric methods, Tseng et al 1 used a glassy carbon electrode stabilized with In 3+ hexacyanoferrate for Cys amperometric detection, obtaining a limit of detection (LOD) of 50 μmol L -1 . Although reproducible measurements with low standard deviations were obtained, the Cys detection was carried out under a highly positive potential of 1.2 V (vs. Ag/AgCl).…”

“…Thus, controlling the content of this amino acid in body fluids, pharmaceuticals and food supplements is of relevance and several analytical methods for Cys determination have been described. Literature describes such determination using spectrophotometric, [5][6][7] spectrofluorimetric, 3,8 chromatographic, 9,10 voltammetric, 2,11,12 capillary electrophoresis 13 and amperometric 1,14,15 procedures. Electrochemical methods present many advantages in comparison to other analytical methods, as simplicity,…”

Recent developments in voltammetric and amperometric sensors for cysteine detection

“…Electrochemical procedures have general advantages such as simpli-cation, high stability and sensitivity, affordable equipment, and on-site supervision. 17,18 Nonetheless, even though L-cysteine is considered to an electro-active molecule, a number of problems have been found in the electroanalysis, such as a larger overpotential, lower sensitivity, as well as inactive electron transfer kinetics at the conventional electrodes. Such barriers may result in the formation of oxides and fouling of the electrode surface.…”