Selective detection ofdopamine using a combined permselective film of electropolymerized (poly-tyramine and poly-pyrrole-1-propionic acid) on a boron-doped diamondelectrode

摘要

An effective and robust electrochemical approach has been developed for selective detection ofndopamine in the presence of 3,4-dihydroxyphenylalanine (L-DOPA), ascorbic acid, uric acid and otherndopamine metabolites. A ‘layer-by-layer’ film of tyramine and pyrrole-1-propionic acid (PPA) wasnformed by subsequent electropolymerization on a boron-doped diamond (BDD) electrode with annoverall thickness of u000133 nm as estimated by AFM. The formation of the electropolymerizednhomogeneous film was also confirmed by SEMand Raman spectroscopy. The modified BDD electrodenexhibited rapid response to dopamine within 6 s and a detection limit of 50 nM with excellentnreproducibility. The stable electropolymerized film was capable of excluding electroactive interferencenfrom 20 mML-DOPA, 20 mM3,4-dihydroxyphenylacetic acid (DOPAC), and ascorbic and uric acids atnnormal physiological conditions (100 mM each). The modified electrode could be used for severalnrepeated analyses of dopamine at 5 mM, without noticeable surface fouling. A plausible mechanism fornpermselectivity was suggested and supported by pertinent experimental data.