TISSUE BIOELECTRODE FOR ORGANIC-PHASE ENZYMATIC ASSAYS

The utility of tissue bioelectrodes to serve as effective organic-phase biosensors is demonstrated. The organic-phase operation enables a simple immobilization procedure, based on spreading a thin layer of the tissue onto a rough graphite disk. Mushroom, banana or horseradish root layers (rich with tyrosinase or horseradish peroxidase) were thus immobilized and employed for quantifying the corresponding phenolic and peroxide species in chloroform media. The thin tissue layer and its immediate proximity to the graphite surface results in a very fast and sensitive amperometric response (8-20 s for steady state, and a detection limit of 3 X 10(-5) M). The influence of numerous experimental variables is explored, and future prospects are discussed.