A new interference-free lysine biosensor using a non-conducting polymer film

An electrochemical biosensor for the determination of lysine to be used for rapid evaluation of food quality has been developed. Platinum electrodes have been coated by electropolymerisation with 1,2-diaminobenzene (1.2-DAB) using cyclic voltammetry. The reduction in the oxidation of interferents compared with the bare platinum electrode was 100% for ascorbic acid, 99% for acetaminophen and 99% for cysteine. The enzyme L-lysine-?-oxidase was then immobilised onto the polymer layer by passive adsorption and a calibration curve for lysine constructed. This gave a linear range of 1 x 10-5 mol/l to 1 X 10-3 mol/l and a limit of detection of 2 x 10-7 mol/l. An electrochemical biosensor for the determination of lysine to be used for rapid evaluation of food quality has been developed. Platinum electrodes have been coated by electropolymerization with 1,2-diaminobenzene (1,2-DAB) using cyclic voltammetry. The reduction in the oxidation of interferents compared with the bare platinum electrode was 100% for ascorbic acid, 99% for acetamin ophen and 99% for cysteine. The enzyme L-lysine-?-oxidase was then immobilized onto the polymer layer by passive adsorption and a calibration curve for lysine constructed. This gave a linear range of 1×10-5 mol/l to 1×10-3 mol/l and a limit of detection of 2×10-7 mol/l.