Electrochemical sensor for bisphenol A based on a nanoporous polymerized ionic liquid interface

Abstract

The ionic liquid 1-butyl -3-[3-(N-pyrrole)-propyl]imidazolium tetrafluoroborate was employed to fabricate a glassy carbon electrode (GCE) modified with a porous film of a polymerized ionic liquid. The resulting film electrode was treated with sodium dodecyl sulfonate solution to exchange the terafluoroborate anions by dodecyl sulfonate groups. This was confirmed by X-ray photoelectron spectroscopy. The morphology of the modified GCE was characterized by scanning electron microscopy and revealed a nanoporous surface. The electrochemical properties of this film electrode were studied by electrochemical impedance spectroscopy using the hexacyanoferrate(II/III) system as an electroactive probe. The response to bisphenol A was investigated by voltammetry. Compared to the unmodified GCE, the oxidation potential is positively shifted, and the oxidation peak current is strongly increased. Experimental conditions were optimized and resulted in an oxidation peak current that is linearly related to concentration of bisphenol A in the 10 nM to ~ 10 μM range. The detection limit is 8.0 nM (at S/N = 3). The electrode was successfully applied to the determination of bisphenol A in leachates of plastic drinking bottles, and its accuracy was verified by independent assays via HPLC.