Competitive CE-UV binding tests for selective recognition of bisphenol A by molecularly imprinted polymer particles

Capillary electrophoresis with ultraviolet detection (CE-UV) was used to perform competitive binding tests to demonstrate the selective recognition of bisphenol A (BPA) by molecularly imprinted polymer (MIP) particles. Cross-linking polymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of BPA yielded MIP particles with an average diameter of 164 ± 15 nm. Their ability to recognize BPA in the presence of nonionic, anionic, and cationic water contaminants was investigated. Binding efficiency was rapidly determined, after sequential injection of particles first and compounds next into the fused-silica capillary provided a short overlapping time during their electrophoretic migrations. The MIP particles exhibited high-binding efficiency (99 ± 1%) for BPA. Neither diclofenac nor metformin affected BPA binding, and 2-hydroxy-4-methoxybenzophenone was even displaced from the particles by BPA. These results verified the high selectivity of MIP toward its target compound.