A Micro Planar Amperometric Lactate Sensor using Differential Pulse Voltammetry

This chapter describes a microplanar amperometric lactate sensor using differential pulse voltammetry. A micro planar biosensor, based on amperometric hydrogen peroxide detection, has been developed for l -lactate determination. This sensor consists of a gold working electrode with a lactate oxidase immobilized membrane and a gold counter electrode, all made on a quartz substrate. The sensor is very suitable for miniaturizing and mass production, because existing semiconductor fabrication processes can be applied. In order to measure lactate concentrations, lactate oxidase immobilized planar gold electrodes were fabricated, and were evaluated by this differential pulse voltammetry method. The lactate sensor gave a linear response with between 0.5–1.5 mM l -lactate concentration. As a typical interference substance, the ascorbic acid influence was evaluated. The sensor output ratio, for 0.5 mM ascorbic acid to that for the same concentration of l -lactate was 0.5 at the 1100 mV potential. The result suggests that l -lactate concentration was accurately measured in the sample containing ascorbic acid.