Simultaneous phase-inversion and imprinting based sensor for highly sensitive and selective detection of bisphenol A

A novel recognition element of molecularly imprinted films (MIFs) was synthesized by wet phase inversion (WPI) on the surface of Ti/TiO2 electrode for highly selective and sensitive electrochemical detection of bisphenol A (BPA). The Ti/TiO2/MIFs sensor was constructed by casting the precursor poly(acrylonitrile-co-acrylic acid) (p(AN-co-AA)) in dimethyl sulfoxide containing template molecule BPA onto the electrode and then immersing into water, resulting in simultaneous p(AN-co-AA) precipitation and BPA imprinting via the facile WPI. The imprinted sites could selectively rebind BPA through hydrogen bonding and hence lead to the equalizing current increase in amperometric detection, by which the BPA could be sensed electrochemically. Accordingly, the Ti/TiO2/MIFs sensor offered a favorable linearity within the wide range over five orders of magnitude (4.4 nM-0.13 mM), and a low detection limit down to 1.3 nM. Excellent recognition selectivity for BPA was also attained over its analogues. Furthermore, this sensor was successfully applied to detect BPA in seawater and paper cup samples, and high recoveries were 86-110% with low relative standard deviations of 1.3-3.2%. By using EPA as a model, the MIFs-based method may provide a facile, rapid, and cost-effective way for ultra sensitive electrochemical measurements of various targeted compounds with good applicability to WPI.