ELECTROCHEMISTRY AND DETECTION OF SOME ORGANIC AND BIOLOGICAL MOLECULES AT CONDUCTING POLYMER ELECTRODES .2. EFFECT OF NATURE OF POLYMER ELECTRODE AND SUBSTRATE ON ELECTROCHEMICAL-BEHAVIOR AND DETECTION OF SOME NEUROTRANSMITTERS

The electrochemical behavior and detection of some molecules of biolog ical significance were studied. The separation and detection of some n eurotransmitters, namely, norepinephrine, L-DOPA, epinephrine, and dop amine were accomplished using reverse phase high performance liquid ch romatography(HPLC) and amperometric detection, respectively. The volta mmetric behavior of these molecules was compared using different polym eric electrodes. Electrocatalytic ''efficiency'' decreases in the orde r of poly(3-methyltbiophene)(P3MT), poly(N-methylpyrrole)(PNMP), poly( aniline)(PAn) and poly(furan)(PF). P3MT showed improved performance as an amperometric detector for HPLC analysis systems over other types o f polymer and conventional electrodes examined. Detection limits as lo w as 10(-8)-10(-9) M were achieved using the P3MT, compared to 10(-6)- 10(-8) M using glassy carbon or platinum electrodes. The nature of the substrate used for the polymer deposition had no effect on the electr ochemical characteristics of the compounds studied. The results descri bes the intrinsic catalytic property of the polymer electrode surface towards the redox behavior of the compounds studied. The polymer elect rode showed promising antifouling resistant against common fouling age nts.