Electrochemically synthesized Pt-MnO2 composite particles for simultaneous determination of catechol and hydroquinone

In this work we report the simultaneous determination of catechol (CC) and hydroquinone (HQ) at electrodeposited Pt-MnO2 particles on glassy carbon electrode. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) results revealed that spherical Pt and MnO2 particles deposited on GCE. Electrochemical impedance spectroscopy (EIS) studies showed that Pt nanoparticles in the Pt-MnO2 composite film help the facile transfer of electrons from MnO2 to the GCE; thereby it decreases the electron transfer resistance (R-et) of the film. The application of the Pt-MnO2 film for the electrocatalysis of CC and HQ was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Well defined voltammetric peaks were obtained for a mixture of equal concentrations of HQ and CC in pH 7 with a peak potential separation of 0.12 V. The simultaneous determination of CC and HQ was done by DPV. The linear range of detection of CC is 15 mu M to 0.447 mM and HQ is 3 mu M to 0.481 mM. Simultaneous determination of HQ and CC in tap water samples has been studied. The film also detects HQ present in skin whitening cream. This report suggests that Pt-MnO2 composite is a promising material for electrocatalytic and electroanalytical applications. (C) 2012 Elsevier B.V. All rights reserved.