Photoelectrochemical Detection of Glucose by Using an Enzyme-Modified Photoelectrode

A new photoelectrochemical method for the determination of glucose based on the photoelectrochemical effect of poly(thionine) photoelectrode to hydrogen peroxide (H2O2) was reported. The H2O2-sensitive photoelectrode was fabricated by electropolymerizing thionine on the surface of ITO electrode. And then glucose oxidase was immobilized on the photoelectrode via the aid of chitosan enwrapping, forming an enzyme-modified photoelectrode. The photoelectrode was employed as an electron acceptor; H2O2 from the catalytic reaction of enzyme was employed as an electron donor, developing an analytical method of glucose without hydrogen peroxidase. In the paper, the photoelectrochemical effects of photoelectrode to H2O2 and glucose were studied. The effects of the bias voltage and the electrolyte pH on the photocurrent were investigated. The linear response of glucose concentrations ranged from 0.05 to 2.00 mmol/L was obtained with a detection limit of 22.0 mu mol/L and sensitivity of 73.2 nA/(mmol center dot L-1). The applied feasibility of method was acknowledged through monitoring the glucose in practical samples.