Molecularly imprinted surface plasmon resonance (SPR) based sensing of bisphenol A for its selective detection in aqueous systems
Bisphenol A (BPA) imprinted poly(ethylene glycol dimethacrylate-N-methacryloyl-L-phenylalanine-vinyl imidazole) [poly(EGDMA-MAPA-VI)] film deposition on a SPR sensor with improved efficiency is described in this paper. The molecularly imprinted SPR sensor was characterized by FTIR-ATR, atomic force microscopy and ellipsometry. A water-compatible molecularly imprinted film has been developed for rapid, sensitive, and label-free detection of BPA in aqueous solutions prepared in Milli Q water, tap water and synthetic wastewater. The real-time response allows the detection of BPA with concentrations ranging from 0.08 to 10 μg L−1 with LOD and LOQ values of 0.02 and 0.08 μg L−1 in Milli Q water, 0.06 and 0.2 μg L−1 in tap water and 0.08 and 0.3 μg L−1 in synthetic wastewater, respectively. A significant increase in sensitivity was therefore expected due to the use of the imprinted poly(EGDMA-MAPA-VI) thin film. The method showed good recoveries and precision for the samples spiked with BPA. The results suggest that the imprinted SPR sensing method can be used as a promising alternative for the detection of BPA. The sensor data fitted well with the Langmuir adsorption model. The selectivity studies showed that the imprinted cavities formed in the polymeric nanofilm recognize BPA preferentially rather than 4-nitrophenol, hydroquinone, phenol and 8-hydroxy quinoline with a relative selectivity coefficient of 2.5, 2.6, 2.7 and 2.5, respectively. The prepared BPA imprinted SPR sensor enables high sensitivity, label-free detection, real-time monitoring, low volume sample consumption, quantitative evaluation, and determination of kinetic rate constants very well. In addition, the SPR based BPA sensor is easy to use and can be a cost effective solution due to the reusability of the prepared sensor. Furthermore, the storage stability will be higher than antibody-based detection methods.