A voltammetric sensor for simultaneous determination of tryptophan and 5-hydroxytryptophan

Abstract

Abstract The present work proposes a method for simultaneous determination of tryptophan and 5-hydroxytryptophan on the carbon-bearing electrode modified with multiwall carbon nanotubes and polyfolic acid. Analytical signals are conditioned by oxidation of tryptophan and 5–hydroxytryptophan from the complex containing polyfolic acid. Preparation of the electrode consists in the formation of the B9 vitamin film on the surface of the carbon-bearing electrode, modified with multiwall carbon nanotubes by the method of cyclic voltammetry. The detection limit of tryptophan and 5-hydroxytryptophan is 1 × 10–7 M.