Abstract
Screen-printed disposable biosensor with dualcarbon working electrodes and an Ag/AgCl reference electrode was developed for simultaneous determination of glucoamylase (GA) activity and glucose. Such determination can be accomplished in 1 min by immobilizing glucose oxidase (GOD) and GOD/starch onto different working electrodes. The method was based on electrochemical detection of glucoamylase-catalyzed glucose from the starch layer coupling with mediator oxidation. Cyclic voltammetry was employed to demonstrate the principle. Chronoamperometry at + 0.4 V versus Ag/AgCl was performed without incubation time. The linear response ranges were up to 20-mmol/l glucose and 150-U/ml GA. The method was applied to the measurements of glucose and GA activity in fungal fermentation process, and exhibited good agreement with the reference method.
ACKNOWLEDGMENTS
This work is partially supported by the Comet Bioelectronics Technology Co., Ltd., Wuhan, China, and the Chinese Academy of Sciences.