NOVEL MEMBRANELESS AMPEROMETRIC PEROXIDE BIOSENSOR BASED ON A TETRATHIAFULVALENE-P-TETRACYANOQUINODIMETHANE ELECTRODE

Amperometric biosensors for the detection of hydrogen peroxide are pre pared by adsorbing peroxidase (POD, EC 1.11.1.7, lipophilized with cap rylic aldehyde) to TTF-TCNQ/silicone oil paste electrodes. This is the first time a reductase is coupled to an organic conducting salt elect rode. At -50 mV vs Ag/AgCl and pH 6.0, the current vs concentration fu nction can be described by the enzyme kinetic Michaelis-Menten formali sm. Stable signals are obtained within 10 s. The detection limit is ty pically in the low nanomolar range for H2O2. The enzyme stability unde r storage, standby, and various operation conditions is discussed.