The Preparation And The Adsorption Properties Of Pyrazosulfuron-ethyl Molecularly Imprinted Polymer And Its Application In The Trace Analysis

Pyrazosulfuron-ethyl (PS) herbicide is widely used to control the annual and perennial broad-leaf weeds and barnyard grasses in directly seeded and transplanted rice paddies due to its high inhibition effect. The interaction of PS with the human serum albumin has been shown to cause changes in the secondary structure of the protein; therefore we should pay attention to the herbicide residues in crops. In order to establish the enrichment and purification method for PS with molecularly imprinted solid phase extraction cartridges; in this study we prepared a new kind of pyrazosulfuron-ethyl molecular imprinted material and the molecularly imprinted solid phase extraction was loaded with this new material.Pyrazosulfuron-ethyl molecularly imprinted polymers (Ps-MIPs) were synthesized by thermo-polymerisation molecular imprinting technique using pyrazosulfuron-ethyl as the template molecule, and methyl acrylic acid (MAA)as the functional monomer. Five kinds of MIPs were synthesized by the three different porogens and three different porogen volumes. The MIP3 exhibited the highest binding capacities for the PS; porogen volume was 36mL of dichloromethane, the amount of binding was 3321.29 μg.g-1, and average particle diameter D50 was 5.36 μm. Comparing the influence of three different adsorption solvents (acetonitrile, dichloromethane, n-hexane) to the adsorption capacity of imprinted polymer molecules, the results show that the maximum solvent adsorption capacity is 1150.71±4.87 μg.g-1 in n-hexane. The adsorption capacity of the five structurally similar herbicides were compared; the results were as follow:PS is 1146.19 μg.g-1, BSM is 1044.21 μg.g-1, NS is 1023.89 ug.g-1, TBM is 1087.27 μg.g-1, MSM is 1051.92 μg.g-1 respectively, and the highest adsorption capacity is PS.The molecularly imprinted phase extraction cartridge was prepared using the synthesis of pyrazosulfuron polymer above. The elution extraction procedure of the molecular imprinting solid phase cartridge was optimized, the results showed that the recovery rate is the highest when using acetonitrile:dichloromethane (1:1, v/v) as the first conditioned solvent, hexane as the loading solvent, and then methanol:acetic (9:1, v/v) as the elution solvent. Finally the pre-treatment methodology for extracting the spiked rice sample using the molecularly imprinted solid phase cartridge was developed prior to reversed-phase high-performance liquid chromatography (HPLC) analysis. Average recoveries of the PS, NS, MSM and BSM were 95.6%,88.6%,87.8% and 89.4%, respectively; but the recovery of TBM was lower (48.2%); the limits of detection ranged from 10.1-50.0μg L-1.