High-Linearity Glucose Enzyme Electrodes for Food Industries: Preparation by a Plasma Polymerization Technique

Abstract

A plasma polymerisation technique was used to prepare high linearity amperometric enzyme electrodes. Two different types of recognition layer for glucose based on oxidases were studied. The first type of recognition layer was prepared in sandwich form with polyethersulphone (PES) and polycarbonate (PC) membranes which were used as inner and outer membranes, respectively. Glucose oxidase was entrapped between these two membranes. The outer surface of PC membranes were further modified by deposition of hexamethyldisiloxane (HMDS) in a glow-discharge reactor to improve linearity. A new type of recognition layer in the form of a single membrane was prepared from cellulose acetate (CA). One surface of the cellulose acetate membrane was modified by deposition of amylamine (AmA) by plasma polymerisation to substitute amino groups on the membrane surface for glucose oxidase immobilisation. Both types of recognition layers were placed separately on a probe type oxygen electrode system with Pt working electrode and Ag/AgCl reference electrode which was polarised at 650 mV. Linearity of these enzyme electrodes were investigated. The linearity of the sandwich type electrode was extended to 600 mM glucose by surface modification of the outer membrane by glow-discharge deposition of hexamethyldisiloxane. The linearity of the single layer enzyme electrode was found to be 1000 mM glucose.