Glucose sensor for flow injection analysis of serum glucose based on immobilization of glucose oxidase in titania sol–gel membrane

Abstract

A novel amperometric glucose sensor was constructed by immobilizing glucose oxidase (GOD) in a titania sol–gel film, which was prepared with a vapor deposition method. The sol–gel film was uniform, porous and showed a very low mass transport barrier and a regular dense distribution of GOD. Titania sol–gel matrix retained the native structure and activity of entrapped enzyme and prevented the cracking of conventional sol–gel glasses and the leaking of enzyme out of the film. With ferrocenium as a mediator the glucose sensor exhibited a fast response, a wide linear range from 0.07 to 15 mM. It showed a good accuracy and high sensitivity as 7.2 μA cm −2 mM −1. The general interferences coexisted in blood except ascorbic acid did not affect glucose determination, and coating Nafion film on the sol–gel film could eliminate the interference from ascorbic acid. The serum glucose determination results obtained with a flow injection analysis (FIA) system showed an acceptable accuracy, a good reproducibility and stability and indicated the sensor could be used in FIA determination of glucose. The vapor deposition method could fabricate glucose sensor in batches with a very small amount of enzyme.