The Use of Diazomethane to Enhance the Selectivity of Bisphenol A Imprinted Polymers

Bisphenol A (BPA) is an estrogen-mimicking chemical that can be selectively extracted from water using a molecularly imprinted polymer (MIP). However, the presence of non-specific binding sites has thusfar limited the utility of BPA-MIPs in sensor applications. This project explored two approaches to reduce or eliminate these sites: Optimizing the molar ratio of functional monomer (methacrylic acid) to cross-linker (ethylene glycol dimethacrylate) to template, or partially esterifying the carboxylic acid residues by site-selective chemical modification via treatment with diazomethane. Results show esterification with diazomethane to be more efficient in blocking non-specific binding sites than optimization of the template to monomer to crosslinker molar ratio. The efficiency and selectivity of the diazomethane-treated molecularly imprinted polymer (TMIP) particles were then compared with those of a commercially available MIP, either uniformly dispersed in the sample solution or densely packed into a cartridge, for solid phase extraction.