The Application Of SPME Coupled With HPLC In Some Pesticide Residues Analysis

Conventional organic sample preparation methods, such as liquid-liquid extraction and solid phase extraction, are time and solvent consuming, and often involve several complicated procedures. Solid phase microextraction (SPME) and microwave extraction (ME) are newly developed sample pretreatment techniques. SPME is a simple and solvent-free extraction technique, which integrates sampling extraction, concentration and sample introduction into a single step. ME can efficiently and selectively extract target analytes from various matrixes by making use of the difference of microwave absorbance capacity between analytes and solvent. The exhaustion of organic solvent can be greatly reduced in ME.In the first part of this thesis, the theory and instrumental setup of SPME were introduced. The development and its application in hyphenation with HPLC were reviewed.The second part of this thesis focuses on the investigation of an analytical method for the determination of three carbamates pesticides (carbofuran, sevin and isoprocarb) in tomatoes by SPME- HPLC. Under the optimized SPME and HPLC conditions, the linear ranges of the method were from 0.1~2mg/kg for carbofuran, sevin and isoprocarb, respectively. The method was used for the determination of the three pesticides in tomatoes. The recoveries were in the range from 91.2 to 94.6%.The third part of this thesis deals with the study of the method development for the determination of carbendazim and thiabendazole in tomatoes based on SPME-HPLC. The conditions of both SPME and HPLC were optimized. The linear range of the method was from 0.1 to lmg/kg, with and the relative standard deviation (RSDs) being 6.5 and 3.8%, respectively. The limit of detection was 0.003 mg/kg for MBC and 0.001 mg/kg for TBZ. The method was successfully used for the determination of carbendazim and thiabendazole in tomatoes, and showed satisfactory result with recoveries in the range from 83.5 to 85.6%.In the fourth part, a method for the determination of diethofencarb in cucumber by SPME-HPLC was established. The conditions of SPME and HPLC were optimized. The linear range of method was from 1 to 1000 jag/kg. The detection limit was0.2|ig/kg. The recoveries fell between 90.6% and 92.8%.In the last part, a method for the determination of some carbamates in cabbage samples by focused microwave assisted extraction (MAE) coupled with SPME-HPLC was preliminarily studied. The conditions of MAE, SPME and HPLC were explored. The MAE-SPME-HPLC method was applied for the determination of carbamates in cabbage samples. The result was satisfactory.