THIN-FILM BIENZYME AMPEROMETRIC BIOSENSORS BASED ON POLYMERIC REDOX MEDIATORS WITH ELECTROSTATIC BIPOLAR PROTECTING LAYER

Amperometric bienzyme sensors were constructed based on solid graphite electrodes modified with polymer redox mediator, horseradish peroxida se and a variety of oxidases and covered with a bipolar electrostatic protective layer. Glucose, ethanol, choline, glycero-3-phosphate and c holesterol sensors were designed and operated at 0 mV vs. Ag/AgCl usin g single potential step chronoamperometry. The protection of the senso r against interference from ascorbic acid and linearity of response we re provided by a bipolar electrostatic layer. Sensitivities as high as 0.74 mu A cm(-2) mM(-1) of glucose, 0.71 mu A cm(-2) mM(-1) of ethano l 5.7 mu A cm(2) mM(-1) of glycerol-1-phosphate, and 28.3 nA cm(-2) pe r 10 mu M of choline, were achieved.