Reduced graphene oxide/gold nanoparticles nanocomposite-modified glassy carbon electrode for determination of endocrine disruptor methylparaben

A modified electrode based on reduced graphene oxide (rGO) and gold nanoparticles (AuNP) dispersed in chitosan (CS) for the voltammetric determination of methylparaben (MePa) is proposed. The characterization of rGO and AuNP was carried out by TEM, ATR FT-IR and UV-vis. The modified electrode was prepared by dropping a AuNP-rGO-CS suspension onto the surface of a glassy carbon electrode (GCE) and characterized by CV and EIS. MePa was electrochemically oxidized at the modified electrode in 0.2 mol L-1 PBS buffer at around +1.0 V. The quantification of MePa was carried out in PBS buffer (pH 8.0) by square-wave voltammetry under optimized experimental conditions: Delta E-s = 3.0 mV, a = 40.0 mV and f = 50.0 Hz. The anodic peak current increased linearly with the concentration of MePa in the range of 0.03 to 1.30 mu mol L-1 (r = 0.998). The limits of detection and quantification obtained from the calibration curve data were 13.77 and 41.73 nmol L-1, respectively. The proposed modified electrode was applied to the determination of MePa in personal care products. Recoveries in the range of 84.3 to 133.5% were obtained. Data provided by the proposed modified electrode were compared with data obtained by UV-vis spectroscopy. The outstanding performance of the electrochemical device indicates that the AuNP-rGO-CS nanocomposite is a promising material for the preparation of chemically modified electrodes for the determination of MePa.