Effects of mediators on the laccase biosensor response in paracetamol detection

An enzyme electrode suitable for paracetamol detection was developed by immobilizing laccase on a dissolved-oxygen probe surface. The immobilization procedure was achieved by means of gelatin, which was then cross-linked with glutaraldehyde. The measurement was based on the detection of oxygen consumption in relation to analyte oxidation. The optimum experimental conditions for the biosensor were investigated and the system was calibrated for paracetamol. Also the effects of three different mediators, namely HBT (1-hydroxybenzotriazole), VLA [violuric acid (5-isonitrosobarbituric acid)] and TEMPO (2,2',6,6'-tetramethylpiperidine-N-oxyl radical) were tested for the biosensor's response. As a result, it was observed that HBT has a remarkable effect on the signal by providing more oxygen consumption during the enzymatic reaction. A linear relationship between sensor responses and analyte concentrations was obtained over the concentration range 2.0-15.0 microM, whereas, in the presence of the mediator HBT, this range became 0.5-3.0 microM.