Improved selective electrocatalytic oxidation of phenols by tyrosinase-based carbon paste electrode biosensor

Tyrosinase-based carbon paste electrodes are evaluated with respect to the viscosity and polarity of the binder liquids. The electrodes constructed using a lower viscosity mineral oil yielded a greater response to phenol and catechol than those using a higher viscosity oil of similar chemical composition. Despite its relatively high viscosity, the use of silicon oil Si PS 086 as carbon paste binder resulted in a 2-fold increase over Si AR 200 and a 4-6 fold increase (over mineral oils) in responses to phenol, p-chlorophenol, and p-cresol. Also reported is the enhanced enzyme electrode response to phenol and catechol resulting from pre-oxidation of these substrates using a plain carbon paste electrode in a series (in-line) dual electrode configuration. (C) 2000 Elsevier Science Ltd. All rights reserved.