BIOSENSING OF TYROSINASE INHIBITORS IN NONAQUEOUS SOLVENTS

An amperometric biosensor based on a Clark oxygen electrode coupled with a biocatalytic layer containing tyrosinase has been developed for measurement in nonaqueous solvents. Glass filter paper was soaked with the enzyme and fixed on top of the electrode by a dialysis membrane. Thiourea derivatives were detected in hexane by evaluating the decrease in the response towards phenol. This method was fast and highly sensitive with detection limits in the range of 13-181 nM depending on the structure of the inhibitor compounds. The response time was up to 10 min and depended on the inhibitor's structure. The mechanism of inhibition is discussed using kinetic parameters.