[Preparation and application of di(2-propylheptyl) phthalate molecularly imprinted solid-phase extraction sorbent]

The molecular imprinted polymer (MIP) with high selectivity to di(2-propylheptyl) phthalate (DPHP) was synthesized by precipitation polymerization with dioctyl phthalate (DOP) as dummy template, methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EDMA) as cross-linker. The binding ability of the template and functional monomer was investigated by UV spectrometry. Compared with the functional monomer acrylic acid (AA), MAA showed stronger binding capacity to DOP and the best combination mole ratio of 6 : 1. The selective adsorption performance of MIP for DOP, DPHP, dimethyl phthalate (DMP) and dibutyl phthalate (DBP) was investigated using the prepared MIP as high performance liquid chromatographic column packing. It was found that the prepared MIP showed higher retention ability and selectivity for DPHP. Using the prepared MIP as a solid-phase extraction (SPE) sorbent (MISPE), the effects of the type and amount of washing solvent and elution solvents on the recovery of DPHP were investigated. After optimization of MISPE profile, the DPHP extraction recovery of 96.8% was obtained when the following procedures were applied to MISPE cartridge: conditioning with 2 mL methanol, loading with 1 mL methanol, washing with 1 mL methanol-water (1 : 9, v/v), eluting with 5 mL methanol-acetic acid (9:1, v/v). The recovery of DPHP on non-imprinted polymer (NIP) cartridge was only 52.9%. The developed MISPE-HPLC method was applied to determine the concentrations of DPHP in rabbit serum at different time points after oral administration. It was found that the maximal concentration (c(max)) and time (t(max)) were 5.88 microg/mL and 4 h, respectively. The recoveries of spiked DPHP in rabbit serum ranged from 90.0% to 92.0% with the relative standard deviations less than 5%.