A biosensor system for chlorophenols using chloroperoxidase and a glucose oxidase based amperometric electrode

A combined electrocatalytic approach using chloroperoxidase and a glucose oxidase electrode has been developed for the measurement of chlorophenol (CP) congeners. Chloroperoxidase possessed a capability to generate a significant or detectable amount of electroactive species from the oxidation of 4-CP, 2,3-dichlorophenol (DCP), 2,4-DCP, 2,5-DCP, 3,4-DCP, 3,5-DCP, 2,3,4-trichlorophenol (TCP), 2,3,5-TCP, 2,3,6-TCP, 2,4,5-TCP, 2,4,6-TCP, and 2,3,4,6-tetraCP. The optimal oxidation conditions were established as 33 mu M chlorophenol, 33 U/mL chloroperoxidase and 1.33 mM hydrogen peroxide for 15 min at ambient temperature. The chlorophenol oxidation products have also been characterized using UV-vis spectrophotometry and cyclic voltammetry (CV). Together with glucose oxidase immobilized on a working glassy carbon electrode (+0.45 V vs. Ag/AgCl), chlorinated oxidation products have been demonstrated as efficient mediators in a glucose oxidase/glucose system. However, the oxidation products from the enzymatic reaction with 2-CP, 3-CP, 2,6-DCP, 3,4,5-TCP, 2,3,5,6-tetraCP and pentachlorophenol were not electroactive or capable of recycling reduced glucose oxidase to its reactive state.