AMPEROMETRIC GLUCOSE BIOSENSOR BASED ON A TETRATHIAFULVALENE-MEDIATEDEPOXY-GRAPHITE BIOCOMPOSITE

An inexpensive, robust, and easily mechanized amperometric glucose sen sor based on a biocomposite material has been constructed. The biocomp osite is made of graphite, a nonconductive epoxy resin, tetrathiafulva lene (TTF) as a redox mediator, and glucose oxidase (GOD). The enzyme retains its bioactivity on confinement in the rigid epoxy-graphite mat rix; with the oxidation current of the reduced mediator serving as the analytical signal (at 150 mV [vs. Ag/AgCl] in a pH 7.00 buffered solu tion featuring 0.1 M phosphate and 0.1 M KCl). The resulting biosensor shows a linear response in the 0.1 to 2 mM glucose range and produces a steady-state signal within a few seconds (11 seconds for a 95% resp onse). Simple polishing procedures can be used to regenerate a freshly bioactive transducer surface.