Synergy of electrocatalysis on photoelectrocatalysis and amperometric determination of trace glucose

Abstract

An amperometric method with synergistic electrocatalysis on photoelectrocatalysis was proposed, and it was used for the detection of trace glucose concentrations for the first time. Under illumination of an external xenon lamp light source, the electrocatalytic oxidation reaction of glucose on a Co3O4-modified electrode produced a synergistic effect on the photoelectrochemical reaction of glucose. The separation of electron–hole pairs generated by the photoelectrochemical reaction was promoted, and the photoelectric conversion efficiency was improved. As a result, the photoelectric current increased, and the sensitivity of the amperometric method was enhanced by about 9 times. The mechanism of synergistic electrocatalysis on photoelectrocatalysis was studied. The method can be used for the determination of glucose with a linear concentration range of 1.0 × 10−8 M to 3.5 × 10−7 M. The sensitivity was 7,753 μA cm−2 mM−1, and the detection limit was 3.6 × 10−9 M. Compared with conventional photoelectrochemical analysis methods, the chronoamperometric method has higher sensitivity and lower detection limit. The method has been used for the direct determination of trace amounts of glucose in saliva and sweat.