Amperometric biosensor for phenols based on a tyrosinase-graphite-epoxy biocomposite.

A new biocomposite, based on the incorporation of the enzyme tyrosinase into a graphite-epoxy resin matrix, was used for the effective biosensing of phenolic compounds. The enzyme retains its bioactivity on confinement in the epoxy resin environment. This renewable (polishable) and rigid bioprobe offers convenient quantification for various phenolic substrates. The fast response (steady-state time = 25 s) accrues from the close proximity of the enzyme and graphite sites. The influence of various experimental variables was explored for optimum biosensing performance. Flow-injection monitoring of phenolic compounds at a rate of 50 samples h-1 yielded a detection limit of 1 x 10(-6) mol l-1 and a relative standard deviation of 1.4% (n = 40).