Tetracyanoquinodimethane-Mediated Flow Injection Analysis Electrochemical Sensor for NADH Coupled with Dehydrogenase Enzymes

A flow injection analysis (FIA) sensor for the oxidation of NADH is reported. The system utilizes a graphite paste electrode modified with the electroactive material tetracyanoquinodimethane (TCNQ). TCNQ acts as an efficient mediator for the oxidation of NADH to biologically active NAD + . Alcohol dehydrogenase/lactate dehydrogenase and NAD + were coimmobilized in TCNQ-modified graphite paste using polyethylenimine to develop a FIA sensor for ethanol/lactate. The system responded rapidly with wide linearity. Response curves for ethanol/lactate and NADH are reported