Ruthenium tris(2,2′)bipyridyl-modified oxidized boron-doped diamond electrode for the determination of Vitamin B6 in the presence of Vitamins B1 and B2

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 (VB6) The oxidization and reduction peak potentials of VB6, are 167.6 and -113 mV, respectively. In the presence of a large amount of Vitamins B, (VB1) and 132 (VB2), the redox peak potentials of VB6 shift slightly while VB1 and VB2 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 VB6 solution (i.e. frequency and amplitude of SWV, pH and scan rate) was investigated. A sensitive square wave voltammetric response for VB6 is obtained covering a linear range from 0.2775 mu M to 0.3686 mM with a detection limit of 6.319 x 10(-8) mol/L in the presence of a large amount of VB1 and VB2. The modified electrode showed good stability and reproducibility with satisfactory recovery results. The determination of VB6 in tablets using this modified electrode showed promising results compared with the traditional methods. (c) 2004 Elsevier B.V. All rights reserved.