Two dimensional palladium nanoparticle assemblies as electrochemical dopamine sensors

Two dimensional assemblies of palladium nanoparticles (PdNPs) were generated by in situ reduction of [PdCl4](2) ions attached to polyethyleneimine silane functionalized silicon and indium tin oxide (ITO) coated glass surfaces. An average size of 7.8 +/- 3.0 nm was determined from atomic force microscopy (AFM) imaging. Surface zeta potential measurements enabled us to track the variation in surface charge during different steps of PdNP generation. Differential pulse voltammetry (DPV) in combination with impedance spectroscopy (IS) was used for the detection of dopamine (DA). A linear range of 2.5-130 mu M was observed for DA alone and in the presence of uric acid and ascorbic acid. In addition, impedance measurements showed an increase in conductance with increasing DA concentration in solution, which led to a calibration curve with a linear range of 0.05- 130 mu M with the detection limit as low as 25 mu M (S/N = 3). (C) 2017 Elsevier B.V. All rights reserved.