A tyrosinase-modified electrode is described to be used as amperometric biosensor for the detection of phenolic compounds in food. The enzyme has been immobilized by drop-coating on a glassy carbon electrode covered by a polyamidic nanofibrous membrane prepared by electrospinning. With respect to others, the selectivity of the designed tyrosinase-biosensor resulted modified by the presence of the nanostructured coating which seems to affect the permeability of phenols as a function of the pH of the solution and of their dissociation constants. The biosensor exhibits a response time of 16 s, a detection limit of 0.05 microM, and a linearity up to 100 microM (slope: -304 nA microM(-1); intercept: -191 nA, r(2)=0.996, n=19). Among others, it can be successfully used for monitoring in real time the release kinetics of phenols encapsulated in polymeric microcapsules.
Copyright 2009 Elsevier B.V. All rights reserved.