Diazonium-functionalized tyrosinase-based biosensor for the detection of tea polyphenols

A tyrosinase-based biosensor was constructed by immobilizing the enzyme on diazonium-functionalized screen-printed gold electrodes. Under optimized conditions, the biosensor exhibited rapid response to the changes in the concentration of all the tested phenolic compounds (catechol, catechin, caffeic acid and gallic acid). Sensitivity, linear range and limit of detection (LOD) were determined, and catechol was found to display the highest sensitivity (36.3 mAM(-1)) and the lowest LOD (0.1 mu molL(-1)). The biosensor was successfully applied to the detection of polyphenols in tea samples.