Anti-fouling properties of an ionic liquid/poly(ionic liquid) gelled electrolyte for the electrochemical detection of bisphenol A

• A leakless IL/poly(IL) gel electrolyte was evaluated for BPA detection • The IL/poly(IL) gel prevents BPA oxidation fouling and electrode passivation • Mild electrode polarisation yields 100% current retention over five SWV scans • This protocol works on Pt thin-film, Pt macrodisk and glassy carbon electrodes A novel anti-fouling strategy has been developed to fully prevent electrode passivation caused by the polymeric by-products from bisphenol A (BPA) electrochemical oxidation. In this work, we utilise a gelled electrolyte comprised of a mixture of an ionic liquid (IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C 2 mim][TFSI]) and a poly(ionic liquid) (poly(IL), poly(diallyldimethylammonium) bis(trifluoromethylsulfonyl)imide, poly[DADMA][TFSI]) to detect BPA. We demonstrate that the IL-based gelled electrolyte possesses an inherent anti-fouling effect, which can be further enhanced by applying mild electrode polarisation prior to BPA detection. Square wave voltammetry (SWV) measurements for BPA oxidation with electrode polarisation confirms the elimination of electrode fouling, demonstrating up to 100% of residual current values across five consecutive measurement cycles (RCV 1-5 ). The polarisation step was shown to be effective on both platinum and glassy carbon electrodes. As a proof-of-concept, electrochemical sensing experiments demonstrated a linear response to BPA concentrations from 200 to 1,200 µM, with a sensitivity of 2.4 nA/µM and a limit of detection of 44 µM.