Electrocatalytic Oxidation of Cysteine at a CoSalophen/n-(butyl) 4SiW12O40 Carbon Paste Electrode

In the present study, a novel mixture consisting of N,N-bis(salicylidene)-1,2-phenylenediamino cobalt (CoSalophen, CoSal) complex and (n-butyl)(4)SiW12O40 (SiW12), have been used to chemically modify a carbon paste electrode (CPE) for sensitive determination of cysteine (CySH). The electrocatalytic effect of the newly developed modified CPE towards oxidation of CySH was evaluated by comparing cyclic and differential pulse voltammograms in the presence of cysteine at bare, CoSal, SiW12 and CoSal/SiW12 modified CPE. The differential pulse voltammetry method was applied as a sensitive method for quantitative detection of CySH trace amounts, the experimental conditions being optimized in order to evaluate the best analytical parameters of the sensor. Reproducibility and stability studies were also performed and the sensor was applied for the determination of CySH in a pharmaceutical sample and in human blood serum and urine samples.