Ruthenium tris(2,2′)bipyridyl-modified oxidized boron-doped diamond electrode for the determination of Vitamin B_6 in the presence of Vitamins B_1 and B_2

摘要

The preparation and electrochemical characteristics of oxidized boron-doped diamond electrode modified by ruthenium tris(2,2′)bipyridyl (Ru(bpy)_3~(3+)) are described. The Ru(bpy)_3~(3+)-modified boron-doped diamond electrode has strong electrocatalytic effects on the redox of Vitamin B_6 (VB_6). The oxidization and reduction peak potentials of VB_6 are 167.6 and — 113mV, respectively. In the presence of a large amount of Vitamins B_1 (VB_1) and B_2 (VB_2), the redox peak potentials of VB_6 shift slightly while VB_1 and VB_2 are not reduced or oxidized on the modified electrode. The catalytic mechanism and the effect of the film thickness were discussed. The influence of various experimental parameters on the Ru(bpy)_3~(3+)-modified boron-doped diamond electrode in VB_6 solution (i.e. frequency and amplitude of SWV, pH and scan rate) was investigated. A sensitive square wave voltammetric response for VB_6 is obtained covering a linear range from 0.2775 μM to 0.3686 mM with a detection limit of 6.319 x 10~(-8)mol/L in the presence of a large amount of VB_1 and VB_2. The modified electrode showed good stability and reproducibility with satisfactory recovery results. The determination of VB_6 in tablets using this modified electrode showed promising results compared with the traditional methods.