Application Of Detection Of Difenoconazole And Bispyribac-sodium Residues In Lotus Root And Water

It is a hot topic and a research direction to find the green,miniature,effective and fast sample pretreatment technology for the diversity of the analysis objects and the complexity of the sample matrix.The polymers are synthesized by moleculary imprinting techniques which could specifically adsorb to a particular target molecule,and could separate the target analytes by their high affinity.Molecularly imprinted polymers as a new type of adsorbent for solid phase microextraction are used to analyze trace substances,with high selectivity,fast mass transfer,reusable,high precision.The metal organic framework ZIF-8 has a high specific surface,stable physical and chemical properties,a uniform pore structure,and the diversity of its structure and performance,so it has a considerable value in solid phase extraction packing.Based on the above two kinds of new extraction adsorbent excellent characteristics,the research content of this paper is as follows:1,Moleculary imprinting-solid phase microextraction as a monolithic column for residue detection of difenoconazole in lake and lotus rootUsing the method of in situ polymerization,the MISPME monolithic column was synthesized by hydrogen bonding in capillary of the glass,and combined with high performance liquid chromatography for detection of difenoconazole in lotus root and lake.The monolithic column was characterized by SEM,BET and FT-IR.The molar ratio of the template molecule to the functional monomer,and the extraction solvent and time,the desorption solvent and time of the solid phase microextraction were optimized.Under the optimal conditions,limits of detection and limits of quantitation of the MISPME-HPLC method were 0.0091 ?g·m L-1 and 0.0300 ?g·m L-1,respectively.In the samples of lake water and lotus root,the recoveries of difenoconazole were in the range of 88.6%-94.7%and 79.7%-101.9%,respectively.This experiment indicated that the method was successfully applied to the detection of difenoconazole in the actual sample.2,Preparation of metal organic frameworks ZIF-8 solid phase extraction column and detection of bispyribac-sodiumThe zinc nitrate hexahydrate and 2-methylimidazole were mixed in a certain proportion by conventional solution method.The reaction was self-assembled into metal organic framework ZIF-8 with methanol as solvent and stirring for 24 h at room temperature.The synthesized ZIF-8 powder was characterized by SEM,FT-IR,BET and XRD.The polished ZIF-8 powder as extraction adsorbent was filled with self-made solid-phase extraction column,and the extraction of bispyribac-sodium were carried out.The self-made ZIF-8-SPE device has obvious adsorption effect on the bispyribac-sodium,while the other eight pesticide extraction effect is poor.The linear range was 0.5 ?g·m L-1to 10.0 ?g·m L-1,the limits of detection was 0.13 ?g·m L-1,and the relative standard deviation is less than 10%.In the ultrapure water samples,the recoveries of bispyribac-sodium were in the range of 85.1%-104.6%.The results showed that ZIF-8-SPE had selective adsorption on the bispyribac-sodium and had good effect.