Selective Determination of Chloramphenicol in Milk Samples by the Solid-Phase Extraction Based on Dummy Molecularly Imprinted Polymer

A novel dummy molecularly imprinted polymer (MIP) for selective extraction and preconcentration of chloramphenicol (CAP) has been successfully developed by precipitation polymerization using thiamphenicol (TAP) as the dummy template, methacrylic (MAA) as the functional monomer, ethylene glycol dimethacrylate (EGDMA) as the cross-linker, and methanol as the porogen. The performances and recognition mechanism of MIPs and non-molecularly imprinted polymers (NIPs) has evaluated in terms of adsorption isotherms and adsorption kinetics. The results showed that the MIPs exhibited significant specific recognition toward CAP in water with a large adsorption capacity. To test the feasibility of MIP in real samples, the obtained MIPs were applied as the selective sorbents for the solid-phase extraction of CAP from milk samples. Under optimized conditions, a rapid, convenient, and efficient method for the determination of CAP in milk samples based on MISPE coupling with high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) was throughly established. The method showed excellent recoveries (96.04~108.68%) and precision (RSDs <7.97%, n = 5) for milk samples spiked at three concentration levels (2, 5, and 10 μg L−1). The results demonstrated that the CAP in milk samples could be separated and purified through molecularly imprinted solid-phased extraction (MISPE), and this method could solve the leakage of template by the employment of dummy template effectively.