Study Of Dynamic Residues Of The Chlorpyrifos From The Production Of Four Medicinal Plant Based On Molecularly Imprinted Technology

In the course of production of the chinese medicinal materials, many pesticides need to be used for controlling the pest and disease damage such as pesticides, fungicides, herbicide et al, which is one of important factors of increase production of the herbs. The influencing factors of quality of the chinese herbs was not only including the effective constituent and heavy metal but also the toxicant such as pesticide residues. Therefore, many pesticides have been widely used in plant of herbs, which possessed of some excellent features such as low toxity, low residues and easy degradation et al, for instance, some organophosphorus pesticide et al; furthermore biopesticide and botanical pesticides have been advocated to used on controlling plant diseases and insect pests. At present, the literature about dynamic residues of chlorpyrifos in four medicinal materials has not been found. This dissertation of the molecularly imprinted matrix solid-phase dispersion(MI-MSPDE) takes typical pesticide as the research objects. After MIPs prepared by molecular imprinting technology(MIT) and used as MI-MSPDE sorbents, MIPs was combined to some analytical techniques for the sake of detecting pesticide residues in herbs. Therefore, this study has selected chlorpyrifos in medicinal materials as researching object and prepared its molecularly imprinted polymers(MIPs), and established analytical method of chlorpyrifos in medicinal materials by using HPLC/GC/GC-MS instrument, which have offered a kind of new thinking and way in analysis of pesticide residues in medicinal materials.The primary research of dissertation of the MI-MSPDE combined with HPLC and GC-MS for detection of chlorpyrifos residues in medicinal materials samples were sufficiently displayed as follows:1) MIPs microspheres were prepared and synthesize by the MIT of surface polymerization on alkylating silica gel with using pesticide named chlorpyrifos as the template molecule. Meanwhile, methylpropenoic acid(MAA) was used as functional monomer, and ethylene glycol dimethacrylate(EGDMA) was used as cross-linking agent in process of preparing MIPs. Furthermore the thermal polymerization method was employed for synthesis of MIPs microspheres with azodiisobutyronitrile(AIBN) used as initiating and triggering agent. Some systematic investigations of synthetic conditions were conducted. Meanwhile, magnesium chloride was used for evidently increasing adsorption amount of MIPs toward chlorpyrifos from the medicinal materials. An off-line MI-MSPDE method followed by HPLC and GC-MS for the analysis of chlorpyrifos was also established. The extraction and purification of detecting analytes on MIPs chromatographic column can successfully cleanup very complicated matrix of samples such as yacon et al, allowing the extraction of the target with high selectivity. 2) The HPLC and GC-MS detection methods of chlorpyrifos from the medicinal materials were established. The univariate analytical approach was used to analysis chlorpyrifos from the medicinal materials, and this method was optimized for detecting target. In the method, the injection volume was set to 20 μL, the flow rate was 0.8 ml/min using acetonitrile and pure water including 0.1% acetic acid(3/1,V/V) as mobile phase, detection time was set 8 min, and UV detecting wavelength was 210 nm, and agilent Eclipse XDB-C8 column(150 mm×4.6 mm,5 μm) was used as separating column which column temperature was 25℃. Then, GC-MS method was also optimized for detecting target chlorpyrifos from the medicinal materials. In the method, analysis of chlorpyrifos insecticides was performed using an Agilent 7890 gas chromatograph(Agilent, CA, USA) equipped with a NPD detector. Furthermore, the analysis conditions of GC-MS were also optimized for detecting target. In the method, the positive ion mode of selected ion monitoring(SIM) with electron impact ionization source was adopted in MS. The EI source was adopted with 70 e V electronic energy, 60μA electric current, 1.00 k V voltage, 200℃ of EI temperature, 250℃ of port temperature, 280℃ of transmission line and 3.0 min of solvent delay. The selecting ion(m/z) were 199, 258, 286, 314. This method was able to satisfy the demand of detecting chlorpyrifos from the medicinal materials. 3) The dynamic residues of chlorpyrifos from Pinellia ternata(Thunb.), Yacon, Ophiopogon japonicas, Wolfiporia cocos et al root medicinal materials were researched in this paper, the testing results have showed that half –life of chlorpyrifos in four medicinal materials was 5.7 ~ 8.0 d when chlorpyrifos was used with recommending dose; merging index of safety interval was 21.8~30.3 d; Half-life of chlorpyrifos from root medicinal materials was less than 5.8-8.0 d when chlorpyrifos was used with high dose; merging index of safety interval was 30.6-35.0 d;the final residues were less than 0.10 mg/kg. 4) The effect of chlorpyrifos towards polysaccharide content in four medicinal materials were researched in this paper. The testing results have showed that the effect of chlorpyrifos towards polysaccharide content in yacon was very evident owing to possessing relationship of positive correlation; but the effect of chlorpyrifos towards polysaccharide content in other three medicinal materials was not evident, merely did it possess a little of acceleration role. 5) The dynamic residues of chlorpyrifos from soil were researched in this paper, the testing results have showed that half-life of chlorpyrifos in soil was 6.0~7.1 d;after about 15 d, the residue was determined less than 10%; the testing results of two year indicated that using dose of chlorpyrifos was one of main factors to affect degradation rate. The final residues of chlorpyrifos were all less than 0.1 mg/kg.