Metsulfuron-methyl Molecularly Imprinted Stir Bar Sorptive Extraction Coupled with High Performance Liquid Chromatography for Trace Sulfonylurea Herbicides Analysis in Complex Samples

Metsulfuron-methyl molecularly imprinted polymer(MIP)-coated stir bar was prepared for sorptive extraction of sulfonylurea herbicides in complex samples. The MIP-coating was about 21.3 mu m thickness with the relative standard deviation(RSD) of 4.4%(n=10). It was homogeneous and porous with good thermal stability and chemical stability. The extraction capability of the MIP-coating was 2.8 times over that of the non-imprinted Polymer (NIP)-coating in hexane. The MIP-coating exhibited selective adsorption ability to the template and its analogues. The extraction conditions, including extraction solvent, desorption solvent, extraction time, desorption time and stirring speed, were optimized. A method for the determination of six sulfonylurea herbicides by MIP-coated stir bar sorptive extraction coupled with high performance liquid chromatography(HPLC) was developed. The linear range was 10-200 mu g/L and the detection limits were within a range of 2.0-3.3 mu g/L. It was also applied to the analysis of sulfonylurea herbicides in spiked river water, soil and rice samples.