Synthesis of magnetic molecular imprinted polymers for solid-phase extraction coupled with gas chromatography-mass spectrometry for the determination of type Ⅱ pyrethroid residues in human plasma

Abstract

Type II pyrethroids has been reported to possess significant toxicity. The analysis of type II pyrethroid residues in biological samples for clinical monitoring and toxicological studies will be favorable. However, due to the interference caused by complex matrix and the trace amount of the pyrethroids, the analysis remains difficult. This study details an efficient method employing magnetic molecularly imprinted polymers as a magnetic solid-phase extraction adsorbent coupled with gas chromatography-mass spectrometry for the detection of type II pyrethroids in human plasma. Molecular simulations were used to screen a suitable monomer and ratio of monomer to template molecule. A series of functional nanoparticles were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy and vibrating sample magnetometer to verify the coating of functional groups. Then, a binding experiment was employed to evaluate the adsorption properties. According to the results of isotherm study, the adsorption sites and capacity of MMIPs are much better than MNIPs, while the maximum adsorption capacity of magnetic molecular imprinted polymers is 27.115 mg g−1. The solid phase extraction conditions were investigated, including eluent type, amount of eluent, extraction time and magnetic molecular imprinted polymers amount. The chromatographic separation of type II pyrethroids in human plasma was carried out by Gas Chromatography-Mass Spectrometry; Linearity was assessed using curves prepared with pyrethroids concentrations of 0.2, 1, 2, 5, 10, 25, 50 ng mL−1; the coefficients of determination were more than 0.990, and the recoveries are within the range of 90.0 and 100.1%. The limits of detection of four pyrethroid pesticides were between 0.005 and 0.032 ng mL−1; The relative standard deviation of magnetic molecular imprinted polymers were 2.74–4.07%. It was confirmed that the current analytical approach can be applied for the selective determination of type II pyrethroids in human plasma samples or other complex matrices.