RESUMO
A sensitive and fast approach has been introduced for the voltammetric sensing of bisphenol A based on modification of a paste electrode with Pt-SWCNTs and 1-ethyl-3-methylimidazolium n-butylsulfate as a highly conductive binder. The new sensor was used to determine the concentration of bisphenol A in food products in I-V mode. The Pt-SWCNTs nanocomposite was synthesized through the polyol method and its morphology was evaluated by field emission scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques. The determining factors influencing the sensing performance, i.e., pH and mediators used in the modification process were optimized in the first step and the results showed that at a pH of 7.0, a modified paste containing 9% (w:w) nanocomposite and 20% (v:v) 1-ethyl-3-methylimidazolium n-butylsulfate formed catalytic properties enhancing the oxidation signal of bisphenol A by 5.9 folds. Current density investigation clearly confirmed the conductivity of Pt-SWCNTs and 1-ethyl-3-methylimidazolium n-butylsulfate in the paste matrix. In addition, fabricated sensor showed considerable sensing behavior for bisphenol A in the concentration range of 0.5 nM-180 µM with a detection limit of 0.2 nM. In the final step, using standard addition technique, the ability of fabricated sensor for sensing bisphenol A in food products was evaluated, and the results confirmed improved performance of the modified electrodes.
