Amperometric Tyrosinase Biosensors Modified by Nanomaterials of Different Nature for Determining Diclofenac

Abstract

Abstract: We developed amperometric biosensors for the determination of diclofenac based on screen-printed platinum electrodes modified by carbon nanotubes in chitosan, fullerene C60 in Boltorn H20, gold nanoparticles in chitosan, and immobilized tyrosinase enzyme. Diclofenac is a reversible tyrosinase inhibitor, which enables its determination using appropriate biosensors modified by nanomaterials in the concentration range from 10 pM to 1 μM with cl = 5 pM. Kinetic studies of the reaction of the enzymatic conversion of phenol showed that, in the presence of diclofenac, noncompetitive inhibition is observed on a tyrosinase biosensor. We tested the procedures for the determination of diclofenac in cow’s milk using the proposed biosensors.