Determination Of Residual Herbicide In Soil By Matrix Solid-phase Dispersion And High Performance Liquid Chromatography Tandem Mass Spectrometry

The pretreatment of complex sample has become an important part of modern analysis method. In view of the matrix components and complex soil samples,this paper uses a semi-automatic matrix solid-phase dispersion extraction of pretreatment method by ball millimg. Not only this method can integrate and purificate meanwhile,but also it can handle multiple samples at the same time. It uses less organic reagent than the traditional method and it greatly improve the efficiency of the pretreatment.Based on matrix solid-phase dispersion extraction by ball milling with high performance liquid chromatography tandem mass spectrometry analysis method,this paper optimize both pretreatment and equipment conditions in detail to determinate the residual herbicides in the soil and use this method above to analyze three methyl urea herbicides and four urea herbicides in the soil. The primary coverage of this thesis as follows:(1) A ball-milling for the matrix solid-phase dispersion extraction-high performance liquid chromatography mass spectrometry has been developed for the determination of the residual urine sulfonyl herbicide in soil. Several conditions were optimized in detail. The best conditions are as follows: 0.2 g soil and 0.8 g HC-C18 solid phase extraction powder was grinding with several small steel balls for 10 min.The mixture was eluted with 10 mL of acetonitrile. The eluent was concentrated to0.6mL with methanol. After the filtration with 0.22?m filter membrane and putting into the automatic sample bottle, then to be analyzed.The results indicated that the chlorsulfuron can achieve the good linearities in the range of 20~200?g·kg-1,and the other two sulfonylurea herbicides achieve the good linearities in the range of10~200?g·kg-1,with correlation coefficients from 0. 9979 to 0.9995.The recoveries at three spiked levels were ranged from 84.7% to 104.6% with RSDs less than7.9%.The limits of detection( LODs) for the target compounds ranged from 0. 32?g· kg-1to 0. 68?g·kg-1. Comparing pretreatment method: Using the semi-automatic matrix solid-phase dispersion extraction by ball milling and traditional soxhlet extraction respectively to extract the three methyl urea herbicides from the soil. Contrast these two extraction methods with the average recoveries and relative standard deviation of the target, it finally concluded that the matrix solid-phase dispersion extraction to extract the target rate is significantly higher than the traditional soxhlet extraction and it shortened 6 times as much as the processing time.(2) A ball-milling based matrix solid-phase dispersion extraction-high performance liquid chromatography mass spectrometry has been developed for the determination of the residual urea herbicides in soil. Several conditions were optimized in detail and the best conditions were as follows: 0.5 g soil and 1.5 g florisil was grinding for 8 min with several small steel balls. The mixture was eluted with 12 mL of dichloromethane with methanol(8:2,V/V). The eluent was concentrated to0.6mL with methanol. After the filtration with 0.22?m filter membrane and putting into the automatic sample bottle, then to be analyzed. Linearities of the four urea herbicides(chlorotoluron?isoproturon?diiuron?linuron)were good from 5 to 100?g/kg.The correlation coefficients ranged from 0.9936 to 0.9990, and average recoveries at two spiked levels were ranged of 71.5%~102.4% with RSD less than9.2%. The LODs of the four urea herbicides were ranged of 0.14~0.56?g/kg.