Preparation of molecularly imprinted polymers for organophosphates and their application to the recognition of organophosphorus compounds and phosphopeptides

Monodisperse molecularly imprinted polymers (MIPs) for diphenyl phosphate (DPP) and 1-naphthyl phosphate (1-NapP) have been prepared by a multi-step swelling and polymerization method using 4-vinylpyridine as a functional monomer, glycerol dimethacrylate as a crosslinker and cyclohexanol or 1-hexanol as a porogen. The retention and molecular-recognition properties of these MIPs for organophosphorus compounds were evaluated by HPLC using a mixture of phosphate buffer and acetonitrile as an eluent. In addition to shape recognition, hydrogen bonding and hydrophobic interactions could play an important role in the retention and molecular recognition of DPP and 1-NapP. Furthermore, the MIPs were applied to the separation of adenosine and adenosine phosphates (AMP, ADP and ATP). These phosphates were retained on the MIPs according to the number of phosphate groups in the molecule and were well separated from one another. Hydrogen bonding and hydrophobic interactions seemed to affect the retention and recognition of adenosine phosphates in low acetonitrile content, while hydrophilic interactions affected these properties in high acetonitrile content. Finally, the MIPs were applied to the trapping of phosphopeptides. The MIPs non-selectively trapped phosphopeptides, which have phosphorylated tyrosine, serine or threonine in the sequences, and successfully trapped four phosphopeptides in tryptic digests of bovine α-casein.