Electrochemical analysis on compounds of the vitamin B6 family using glassy carbon electrodes

Abstract

The electrochemical reduction of vitamin B6 group and related compounds has been performed at pH neutral using glassy carbon electrodes. Irreversible bi- or tetra-electronic processes controlled by diffusion on the top of the wave are observed for these substances by cyclic voltammetry. In most cases the first electron transfer was the rate determining step of the electrode process. In depth electroanalytical behaviour of the most important members of the vitamin-6 family, from a biological point of view, is also presented. Limits of detection (99, 59, 286 and 19 μM respectively), linearity ranges (200-1000, 100-800, 400-1600 and 40-200 μM respectively) precision as RSD(%) (0.45, 4.11, 6.45 and 4.98 % respectively) and recovery (%) values (99.7, 97.7, 104.4 and 98.9) for Pyridoxal, Pyridoxal-5’-Phosphate, Pyridoxamine and Pyridoxic Acid are presented. The use of glassy carbon electrodes for the analysis of urine samples gives an example of the potential use of these for the analysis of biological samples