EFFECT OF SURFACE-ACTIVE AGENTS ON AMPERO METRIC NADH MEASUREMENTS WITH GLASSY-CARBON BASED CHEMICALLY-MODIFIED ELECTRODE

A special electrochemical pretreatment was employed in the case of fin ely polished glassy carbon electrode surface to increase the adsorptio n of Meldola Blue (7-dimethylamino-1,2-benzo-phenoxazin) redox mediato r. The chemically modified glassy carbon electrode holding the adsorpt ive mediator layer could be used to measure amperometrically.NADH conc entration. The interfering effect of non-ionic surfactants was studied in the case of NADH measurements. The glassy carbon based electrode r esponse was less affected and could be regenerated much more easily th an the response of a similar spectrographic-graphite based electrode s tudied earlier. Surface-active agents can influence the virtual covera ge of the surface by the mediator.