ELECTROOXIDATION OF LACTOSE ON PLATINUM AND ON MODIFIED PLATINUM-ELECTRODES IN ALKALINE-MEDIUM

In this preliminary work, the electro-oxidation of lactose was investi gated by cyclic voltammetry in alkaline medium on platinum electrodes. Tafel slopes and variation of electrochemical parameters indicated th at the electrocatalytic oxidation of lactose was controlled by diffusi on. The current densities were small, but underpotential deposition of metal adatoms (Bi, Pb and Tl) was found to give rise to large increas es in the current densities of lactose oxidation. One of these systems (eg Pt-Bi) was used to realize long-time electrolysis with a triple p ulse potential programme. The analysis of solutions was performed by i onic chromatography (HPIC) at regular intervals during lactose oxidati on. High selectivity was achieved and lactobionate was the sole reacti on product detected, with a conversion rate of ca 70% of the initial l actose after only two hours of electrolysis.