Study On A Method For Determination Of Trichlorfon And Monocrotophos Residues Based On Molecular Imprinting Technology

Organophosphorous pesticides can control the quantity of pests and weeds in a broad range effectively. They play an important role in promoting the development of agricultural modernization. However, organophosphorous pesticides have become the most serious pollution pesticides because of their unreasonable using. Their health effects in primary agricultural products have attracted increasing attention worldwide. Therefore, in addition to strengthening the management of organophosphorous pesticides, developing a simple, fast, sensitive and efficient detection method to control the pesticide residues in food is necessary.In this study, a new molecularly imprinted polymer was prepared, which could selectively adsorb the trichlorfon and monocrotophos. Thus, the method of molecularly imprinted solid-phase extraction coupled with high-performance liquid chromatography(MISPE-HPLC) for the simultaneous determination of trichlorfon and monocrotophos was established. The main results include:1. A molecularly imprinted polymer(MIP) that can selectively recognize both the trichlorfon and the monocrotophos was prepared by bulk polymerization using the mixture of trichlorfon and monocrotophos(1.5 : 1, mol/mol) as template molecules, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as cross-linker, and azodiisobutyronitrile as initiator. The polymerization conditions were optimized in detail. Dynamic and Static adsorption experiments showed that the MIP exhibited good recognition ability and higher selectivity compared with the NIP.2. Using metal-organic framework MIL-101 as support carrier, a novel MIL@MIP was synthesized through optimized bulk polymerization. The prepared MIL@MIP was characterized by FT-IR, SEM, TGA, static adsorption experiment, kinetic adsorption experiment and competitive adsorption test. Then, using the MIL@MIP as sorbent material, a method of solid phase extraction coupled with HPLC for detection of trichlorfon and monocrotophos in fruit was developed. Under the optimal conditions,the limit of detection of this method for trichlorfon and monocrotophos was 1.14 ?g L-1 and 1.47?g L-1, respectively. The pear and apple samples spiked with the two kinds of organophosphorus pesticides were extracted and determined by this method with good recoveries ranging from 86.5% to 91.7%. The RSD for three replicate extractions of spiked samples was 1.8% to 3.7%. Moreover, this method was also successfully applied for the detection of the two organophosphorus pesticides in the strawberry and kiwi fruit samples.