Investigation On Sample Preparation Techniques For Pyrethroids Residues In Foodstuffs

Vegetables and tea are indispensable constituents of the human meal throughout the world. Therefore, agricultural production may represent a significant source of human exposure to pesticide residues.After high poisonous organophosphates was forbidded. Synthetic pyrethroids are widely used as pest control agents in agricultural production because of their satifactory efficiencies, low toxicity and their non-persistence in the environment. However, the widespread use of pesticide in fruit and crop directly has led to the presence of pesticide residues in vegetable and tea. Currently, determination techniques for pyrethroids in vegetables and tea are advanced, but sample preparation techniques comparatively fall behind. Therefore, establishment of sample preparation techniques for pyrethroids residues in vegetables and tea is urgent matter.In the research, self-made Florisil solid-phase extraction combined with ultrasonic solvent extraction were proposed. A high performance liquid chromatographic (HPLC) method for simultaneous determination of five synthetic pyrethroid insecticide residues in vegetable and tea, namely fenpropathrin, lambda -cyhalothrin, deltamethrin, fenvalerate and permethrin.Solid-phase extraction method for the clean-up the extracts of synthetic pyrethroid insecticide residues in vegetables was optimized. A column packed with Florisil and top packed with active carbon. The effects of different eluted solvent on the clean-up of five pyrehtroids in the vegetable sample were investigated. Best recovery was achieved using 10 mL petroleum ether/acetone(20:80,v/v) as eluted solvents. The preparation for six kind samples with five pyrethroids by this method. The recoveries for cabbage,cauliflower,carrot,green pepper,vase greens,mustard were 80.7%～107.8%, 77.8%～102.6%, 59.9%～109.3%, 63.7%～109.0%, 49.3%～95.7%, 50.1%～96.5% and...