Voltammetric determination of glutathione in haemolysed erythrocyte and tablet samples using modified-multiwall carbon nanotubes paste electrode.

A chemically modified electrode was prepared by incorporating p-aminophenol into multiwall carbon nanotubes paste matrix. Cyclic voltammetry, square wave voltammetry, double potential step chronoamperometry, and electrochemical impedance spectroscopy were used to investigate the electrochemical behaviour of glutathione at the chemically modified electrode prepared. According to the results, p-aminophenol multiwall carbon nanotubes paste electrode (p-APMWCNTPE) showed high electrocatalytic activity for glutathione oxidation, producing a sharp oxidation peak current at about +0.

A voltammetric sensor for the simultaneous determination of L-cysteine and tryptophan using a p-aminophenol-multiwall carbon nanotube paste electrode.

Two amino acids, L-cysteine and tryptophan, could be simultaneously determined in an aqueous solution (pH 6.0) using a carbon nanotube paste electrode (CNPE) modified with p-aminophenol as a mediator. The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of L-cysteine, leading to an overpotential reduced by more than 550 mV.