Ultra-Selective dopamine detection in an excess of ascorbic acid and uric acid using pristine palladium nanoparticles decorated graphene modified glassy carbon electrode

Abstract

In the present work, we report the electrochemical detection of dopamine (DA) by means of cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CA) in the presence of excess ascorbic acid (AA) and uric acid (UA) using pristine palladium nanoparticles decorated graphene modified glassy carbon electrode (G/PdNPs-GCE). G/PdNPs nanocomposite was synthesized by preparing pristine PdNPs from its precursor palladium acetylacetonate, with morpholineborane as the reducing agent and subsequently assembled them on graphene nanosheets. The nanocomposite was characterized by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), UV-Vis spectrophotometry and Fourier transform infrared spectroscopy (FTIR). CV, DPV and CA determination of DA showed distinct increase in the current with increasing concentration and a wide range of linearity. The catalytic material exhibited ultra selective detection of dopamine with a peak to peak separation of 90 and 149 mV for AA-DA and DA-UA oxidation respectively. The reduced overpotential for simultaneous oxidation of DA, AA and UA in DPV and CV is also a remarkable feature of the catalytic material. More importantly, the modified electrode exhibited clear and distinct peak for DA in CV and DPV even in the presence of 300 and 450 times excess of AA and UA respectively.