Electrocatalytic Oxidation of Tryptophan at Gold Nanoparticle-Modified Carbon Ionic Liquid Electrode

The electrochemical oxidation of tryptophan was studied at the carbon ionic liquid electrode (CILE) modified with gold nanoparticle (GNP). This electrode has a stable and excellent response toward tryptophan. The oxidation of tryptophan at a GNP/CILE in phosphate buffer solution (pH=7) appears to be chemically irreversible at potential of 0.65 V vs Ag/AgCl. Comparative experiments were carried out using carbon paste electrode (CPE) and glassy carbon electrode (GCE). Under optimal experimental conditions, the calibration curve was linear in the tryptophan concentration range from 5 to 900μM with an excellent correlation coefficient (0.9955). The limit of detection was 4μM. The results indicate that contrary to many other electrodes, the oxidation of tryptophan on GNP/CILE does not result in electrode fouling.

Keywords:

Tryptophan , Carbon ionic liquid electrode , Gold nanoparticle