Electrochemical oxidation of histamine and serotonin at highly boron-doped diamond electrodes

The electrochemical oxidation of histamine and serotonin also known as 5-hydroxytryptamine (5-HT) was studied using polycrystalline, boron-doped diamond thin film electrodes. The oxidation reactions were studied using cyclic voltammetry, hydrodynamic voltammetry and flow injection analysis (FIA) with amperometric detection. Highly reproducible and well defined cyclic voltammograms were obtained at diamond electrodes, with a peak potential of +1.4 V vs SCE for histamine and +0.38 V vs. SCE for 5-HT. These voltammograms also indicated a relatively low adsorption of oxidation products on the diamond surface. A detection limit of 0.5 mu M for histamine was obtained by use of the FIA technique with amperometric detection at a diamond electrode, and a remarkably low detection limit (10 nM) was obtained for 5-HT by the same method.