Study on Extraction of Pyrethroid Pesticide Multi-Residues in Tea by GC/MS

The factors of extracting pyrethroid pesticide multi-residues from tea were studied, especially for the influence of adding water into samples before organic solvents extraction. Results show that higher extracting efficiency is acquired without adding water. A simple and accurate pretreatment for pyrethroids in tea is reached by optimizing the choices and volumes of eluting solvents. The samples without water immersing were extracted by 50 mL of V(hexane)∶V(acetone)=1∶1, followed by cleaning up with columns of activated carbon and Florisil respectively. 15 mL of V(hexane)∶V(ethyl acetate) =2∶1 was employed to elute the Florisil column, then was determined by GC/MS. The recoveries range from 81% to 120%, RSDs are 2.2%-7.8%, and the limits of detection are 0.002-0.01 mg•kg^-1.