Preparation of activated carbon from date stones as a catalyst to the reactivity of hydroquinone: Application in skin whitening cosmetics samples

In this study, the authors report on the use of the date stones as a raw material for the production of activated carbon (AC) using the physical activation. The as prepared activated carbon were first characterized using X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) Spectroscopy, Scanning Electron Microscopy (SEM/EDX) and chemical methods, and then used as modifier agents for the carbon paste electrode (CPE) to study the electrochemical behavior of the hydroquinone (HQ). This electrochemical study was carried out using the cyclic voltammetry, the chronoamperometry and the differential pulse voltammetry (DPV). The Box-Behnken experimental design (BBD) of the response surface methodology was employed to investigate the effect of different parameters of the AC preparation on the peak potential of the hydroquinone. The transfer coefficient a, the apparent electron transfer rate constant k(s) and the electro-catalytic activity K for the redox reaction of the hydroquinone at the surface of the AC-CPE were determined using electrochemical approaches. Differential voltammetric measurements of the hydroquinone at the modified electrode exhibited the linear range of 5.0 x 10(-8) mol L-1 to 1.0 x 10(-3) mol L-1 with a low detection limit of 3.6 x 10(-8) mol L-1. Finally, this method was applied for the determination of HQ in skin whitening cosmetics samples. (C) 2019 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi.