Preparation And Evaluation And Enrichment Of Magnetic Dual-template Imprinted Polymers For Organophosphate Pesticides

Objective:In this research,a method for the selection and enrichment of organophosphorus pesticides?OPPs?residues in complex sample matrices by magnetic molecularly imprinted solid phase extraction was established.?1?A method for magnetically dual-template molecular imprinted polymers was firstly established;?2?The two template molecules were analyzed by magnetically molecular imprinted solid phase extraction combined with gas chromatography mass spectrometry?MSPE-GC-MS?;?3?A simple method for simultaneous enrichment and analysis of twelve organophosphorus compounds in cabbage matrix by MSPE-GC-MS was established.Methods:The magnetic dual-template molecularly imprinted polymer was synthesized by surface imprinting method with methyl parathion and quinothione as double templates,methacrylic acid and 4-vinylpyridine as functional monomers,glycol dimethacrylate as cross-link agent,azodiisobutyronitrile as initiator,acetonitrile as solvent,superpara-magnetic Fe₃O₄@SiO₂ as magnetic carrier.The morphology and structure of the polymer were characterized by Fourier transform infrared spectroscopy?FT-IR?,scanning electron microscopy?SEM?,X-ray diffraction?XRD?and vibrating sample magnetometer?VSM?.At the same time,the experimental conditions of polymer synthesis were optimized.In addition,two single template imprinted polymers and non template imprinted polymers were synthesized as positive and negative controls.The magnetic dual-template molecularly imprinted polymer?MIP?was used as solid phase extraction?SPE?packing for sample pretreatment.Results:?1?The morphology,crystal structure and magnetic properties of the polymers were good.?2?Dual-template imprinted polymers have advantages over two single template and non imprinted polymers in the simultaneous analysis of multiple analogues.?3?The established MSPE-GC-MS analysis method had good linear range?0.01-0.8?g/mL?,recovery rates?81.5-113.4%?and detection limits?1.62-13.9 ng/m L?for 12organophosphorus pesticides.Conclusion:?1?The dual-template magnetic molecularly imprinted polymer with methyl parathion and quinalphos as templates achieved rapid and selective enrichment of multiple OPPs from complex sample matrices;?2?The magnetic dual-template molecularly imprinted polymers were more selective than single-template or non-template polymers;?3?The pretreatment of the MSPE-GC-MS method took only ten minutes to reach the adsorption equilibrium,which was not only sensitive and efficient but also time-saving.