Determinação Simultânea de Hidroquinona e Bisfenol A em um Eletrodo de Pasta de Carbono Modificado com Nanopartículas de Prata

A rapid and sensitive electrochemical sensor for the simultaneous determination of hydroquinone (HQ) and bisphenol A (BPA) has been proposed modifying a carbon paste electrode (CPE) with silver nanoparticles (nAg) and polyvinylpyrrolidone (PVP). HQ and BPA are phenolic compounds highly abundant in nature, they are essential raw materials and by products of numerous chemical industries. Especially, BPA can disrupt the endocrine system of humans, cause cancer, infertility, diabetes and obesity. In addition, HQ can cause fatigue, headache, tachycardia and kidney damage in human. These compounds are extremely harmful to animals, plants, and aquatic environments even at very low concentrations[1,2]. Therefore, it is of great significance to propose a sensitive method to detect simultaneously HQ and BPA.The nAg were synthesized by the reduction of silver nitrate using PVP. The nAg-PVP material obtained was characterized by transmission electron microscopy, X-ray diffraction and UV–vis spectroscopy. The modified carbon paste electrode (nAg-PVP/CPE) was prepared by hand mixing, in a mortar, in which graphite powder, mineraloil and nAg-PVPwere in the weight ratio of 75/20/5. The electrochemical behavior of HQand BPAat nAg-PVP/CPE in 0.1 mol L−1B-R buffer(pH 6.0) were investigated using cyclic voltammetry.The results indicatedthat the electrochemical responses are improved significantly at the modified electrode. The enhancement in the HQ and BPA oxidation peak currents for the nAg-PVP/CPE in comparison with CPE is mainly ttributed to the significant increment in the electroactive area of the electrode due to the presence of silver nanoparticles, justifying its use for detection of HQ and BPA.The calibration curves for HQ and BPA was obtained by square wave voltammetry under optimized experimental: f = 50.0 Hz, a = 30.0 mV and ΔEs = 2.0 mV. The calibration curves showed an excellent linear response and the detection limits for the simultaneous determination of HQ and BPA were 0.07 μmol L-1and 0.15 μmol L-1, respectively. The applicability of the method was demonstrated by the recovery studies of HQ and BPA in water samples.