Preparation of l-lactate Biosensor that uses Polyion Complex Membrane Containing Peroxidase and Ferrocene

Abstract

In order to detect lactate, high sensitivity lactate sensor was completed by attaching lactate oxidase (LOD) to the hydrogen peroxide sensor. The hydrogen peroxide sensor was prepared as follows; poly(4-styrenesulfonate), peroxidase (POD), ferrocene and poly-l-lysine solutions were dropped on a glassy carbon electrode. After drying this electrode, LOD and glutaraldehyde solutions were dropped on the membrane to immobilize the enzyme. The electrode was immersed into a buffer solution (pH 6.5), and a potential of −0.2 V vs. Ag/AgCl was applied to detect the reduction current. Immediately after the addition of l-lactate (10 µM) to the test solution, the reductive current increased and reached a plateau within 20 s. The lower detection limit was 1 µM (S/N=3), and the ratio of the response for the interferent to that for l-lactate on the electrode was 0.18.