Development of neurotransmitter sensor using Polycarbazole

In undertaking this study a primary goal was to develop an electrode which will be selectively sense dopamine or L-dopa in the presence of ascorbic acid/adrenaline. In the literature carbon paste electrode, graphite epoxy electrode etc. have been employed to achieve the selectivity. The need to go through the treated electrode has been to solve the selectivity problem. The results reported in this thesis on the electrochemical oxidations of dopamine or L-dopa at polycarbazole electrode reveals that these molecules are oxidised at the electrode (0.2-0.5 V) and the product o-quinone undergoes a chemical reaction as the cyclic voltammetric complementary peak is absent. The chemical reaction has been identified by earlier studies as intra molecular cyclisation leading to melanin. This electrode introduces a greater reversibility in the electrochemical measurements and reproducibility in the analytical measurements of concentrations of dopamine, L-dopa and adrenaline. These endogenous amines are distinguishable at the polycarbazole electrode; the electrode does not sense adrenaline in the presence of the other two.