Simultaneous and sensitive determination of hydroquinone, catechol, and resorcinol with a palladium...

In this study, catechol (CC), hydroquinone (HQ), and resorcinol (RC) - dihydroxybenzene isomers - were determined simultaneously using the composite surface. The proposed material was prepared via electrochemical polymerization of Bromocresol Green (BCG) followed by electrodeposition of palladium nanoparticles (Pd). The developed electrode was characterized using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and X-ray Energy Dispersive Spectroscopy (EDX) techniques. Electrochemical measurements were performed using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in pH 7 phosphate buffer solution. The Pd nanoparticle deposited polymerized BCG-modified glassy carbon electrode (Pd/Poly(BCG)/GCE) displayed enhanced current sensitivity for all three isomers compared to a bare GCE and Poly(BCG)/GCE. Thus, this was attributed to the synergistic effect of the improved active surface area of Poly(BCG) and the unique properties of Pd nanoparticles. Under optimized conditions, three well-separated oxidation peaks were achieved by DPV for HQ (19 mV), CC (130 mV), and RC (430 mV) at the Pd/Poly(BCG)/GCE during the simultaneous concentration change of the isomer mixture. The limit of detection values (S/N = 3) were found to be 89 nM, 74 nM, and 98 nM for HQ, CC, and RC, respectively. Thus, the high sensitivity, adequate reproducibility, good stability, and easy preparation of the Pd/Poly(BCG)/GCE surface made it a promising candidate for the determination of dihydroxybenzene isomers.