EFFECT OF SURFACTANTS ON THE SIGNAL OF CHEMICALLY-MODIFIED AMPEROMETRIC ELECTRODES

A special electrochemical pretreatment has been employed for a finely polished glassy carbon electrode surface to increase the adsorption of Meldola blue (7-dimethylamino-1,2-benzo-phenoxazine) redox mediator. The chemically modified glassy carbon electrode holding the adsorptive mediator layer can be used to measure NADH concentration amperometrically. The interfering effect of non-ionic surfactants has been studied in the case of NADH measurements using a rotating-disc electrode technique and flow-injection analysis (FIA) measurements. The glassy carbon electrode response is less affected and could be regenerated much more easily than the response of a similar spectrographic graphite-based electrode studied earlier. Surface-active agents can influence the apparent coverage of the surface by the mediator.