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 biological significance were studied. The separation and detection of some neurotransmitters, namely, norepinephrine, L-DOPA, epinephrine, and dopamine were accomplished using reverse phase high performance liquid chromatography(HPLC) and amperometric detection, respectively. The voltammetric behavior of these molecules was compared using different polymeric electrodes. Electrocatalytic ''efficiency'' decreases in the order 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 of polymer and conventional electrodes examined. Detection limits as low 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 electrochemical characteristics of the compounds studied. The results describes the intrinsic catalytic property of the polymer electrode surface towards the redox behavior of the compounds studied. The polymer electrode showed promising antifouling resistant against common fouling agents.