| Organophosphate pesticides chlorpyrifos (CPF) is effective broad-spectrum insecticide and herbicide. For the prohibition of using highly toxic and easy residues pesticide in agricultural production, CPF as a good alternative become widely used. CPF could be accumulated by plant and transfer to the human body through the food chain. It has been the major item of pesticide residue examination. According to the recently research, since the large amount of base, CPF has become one of the most common pesticides in vegetables found by examinations, although the rate of over-limits is stay low. Liquid-Liquid Extraction (LLE) and Gas Chromatography (GC) is used as CPF testing method in current national and industry standards. This method leads to tedious steps, also cost large amount of organic solvents, which easily lead to environmental pollution. In addition, because the matrix elements of food and environment samples are complex, the trace target elements are hard to detect.Molecular imprinting technology (MIT) is a simple and controllable way to prepare functional materials which has specific adsorption on target molecule. Molecularly imprinted polymers (MIPs) could separate and enrich target components at the same time. The superiorities of MIPs could make up the weak points of traditional methods, such as specificity, stability, reusability and prepared low costs. In this article, Bulk polymerization and precipitation polymerization are used separately to prepare MIPs, using CPF as template molecular, using methacrylate (MAA) as functional monomer, using ethylene glycol dimethacrylate (EDMA) as cross-linker, using azobisisobutyronitrile (AIBN) as itnitiator. Technology of Molecularly Imprinted Solid Phase Extraction (MISPE) and Molecularly Imprinted Sensor (MIS) are discussed in the application of CPF testing.The results show that, MIPs prepared by Bulk polymerization are inμm-level, using toluene as solvent. There are two kinds of binding sites between MIPs and CPF, with the molar ratio of 1:2. Their apparent maximum number (Qmax) and equilibrium dissociation constant (Kd) are calculated and conclud that Qmax,1=201.6nmol·g-1, Kd,1=455.4μmol·L-1, Qmax,2=775.4nmolμg-1,Kd,2=48.0μmol·L-1. This MIPs are used in MISPE with the recovery rate nearly 90%. Also it shows great elective to BHC, triadimefon, procymidone, malathion and phorate, which with the unsimilar structure of CPF.MIPs prepared by precipitation polymerization with the uniform size of 100-200nm, using acetonitrile as solven. Infrared Spectroscopy (IR) result shows that, MIPs and CPF combined with hydrogen bond. There are two kinds of unequal binding sites with the different Qmax and Kd (Qmax,1=321.6nmol·g-1, Kd1=283.0μmol·L-1, Qmax,2=869.6nmol·g-1, Kd2=56.1μmol·L-1). This MIPs are used to build MIS, using PVC as adhesives. A three-electrode system is used in the MIS, that is using modified gold electrode as working electrode, using Ag/AgCl electrode as reference electrode, using platinum wire as auxiliary electrode. Constant current-potential method is used in the detection with the response time of 10min. MIS shows excellent linearity with the concentration range of CPF at 10-12 mol·L-1-2×10-8mol·L-1. The linear equation is y=11.26x+157.9 (R2=0.9697), detection limits is10-12mol·L-1, and the appropriate range of pH is 2.2-3.4. MIS displays excellent elective to dimethoate, malathion, phorate and atrazine. In the actual testing, MIS got a score that the recovery rate of water samples range from 88.4% to 105.7% with the standard deviation is 8.2 and of vegetable amples range from 84.4% to 89.5% with the standard deviation is 2.3.Both the theoretical and applied research are innovative in this article, since MIT hasn't been found in the detection of CPF. Compared with traditional method, MISPE and MIS have shown incomparable superiority. Although the research is still at the laboratory stage, but the development and applications of MIT Can be expected a very important practical significance and broad market prospects.
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