Effect of pre-treatment of platinum for modified platinum wire glucose oxidase amperometric electrodes

Abstract

A micro-amperometric enzyme electrode, suitable for flow injection analysis and based on platinised platinum wire (100 µm diameter), is described. The system was tested for glucose oxidase covalently attached to the activated electrode surface with glutaraldehyde. Comparisons were made with micro-enzyme electrodes based on anodised platinum and thermally oxidised platinum wire, each linked to glucose oxidase. The response and wash times of each system were <25 and ca. 30 s, respectively. The platinised platinum enzyme electrode exhibited enhanced signals and a wider range towards glucose (0.005–30 mM) compared with the anodised platinum and thermally oxidised platinum systems (0.05–30 mM). Also, the lifetimes of 15 h obtained for both the platinised platinum wire and the thermally oxidised platinum wire systems considerably exceeded the 9 h obtained for the anodised platinum electrode when these electrodes were subjected to a continuous flow of 10 mM glucose. The lifetimes for all four systems during normal flow injection analysis exceeded 10 d.