Sensitivity control of dopamine detection by conducting poly(thionine)

Abstract We investigated conducting poly(thionine) (PTH) films prepared by single-step and double-step electrochemical methods (PTH-S and PTH-D, respectively) on the surface of a glassy carbon electrode (GCE) for the detection of dopamine (DA) with varying sensitivity. Electrochemical and spectroscopic analysis revealed that both PTH films have identical chemical structures, but the sensitivity of DA detection was significantly dependent on the polymerization conditions. A simple variation of the electropolymerization conditions dramatically changed the catalytic activity of the PTH films towards the oxidation of DA in the presence of ascorbic acid (AA) and uric acid (UA) as well as the PTH formation mechanism. PTH-D was found to have a higher surface charge than PTH-S, and also showed a sensitivity enhancement for DA detection of up to one order of magnitude compared to PTH-S.