Cyclic Voltammetry In Alkaline Medium Research Articles

Electrooxidation of pyridoxal (PL) on a polycrystalline gold electrode in alkaline solutions

Abstract The electrooxidation of pyridoxal (PL) on a polycrystalline gold electrode is studied by cyclic voltammetry in alkaline media. Two oxidation peaks, A and B, are obtained in the positive scan within the potential range of the double-layer region. The behavior observed allows to propose an oxidation mechanism where the anion hemiacetal (ha − ) and hemiacetal (ha) are the electroactive species for peaks A and B, respectively. The oxidation product for both peaks is pyridoxic acid, in agreement with the analysis of the products obtained after controlled potential electrolysis.

Electro-oxidation of lactose on platinum and on modified platinum electrodes in alkaline medium

In this priliminary work, the electro-oxidation of lactose was investigated by cyclic voltammetry in alkaline medium on platinum electrodes. Tafel slopes and variation of electrochemical parameters indicated that the electrocatalytic oxidation of lactose was controlled by diffusion. The current densities were small, but underpotential deposition of metal adatoms (Bi, Pb and Tl) was found to give rise to large increases in the current densities of lactose oxidation. One of these systems ( eg Pt-Bi) was used to realize long-time electroysis with a triple pulse potential programme. The analysis of solutions was performed by ionic chromatography (HPIC) at regular intervals during lactose oxidation. High selectivity was achieved and lactobionate was the sole reaction product detected, with a conversion rate of ca 70% of the initial lactose after only two hours of electrolysis.