Determination of Pyrethroids Residues in Tea by High Performance Liquid Chromatography with Ultrasonic Extraction

Five pyrethroids residues in tea including fenpropathrin,lambda-cyhalothrin,deltamethrin,fenvalerate and permethrin were determined by high performance liquid chromatography with ultrasonic extraction.With extraction reagents of n-hexane/acetone(30/70,V/V) for 60min,and then cleaning up with florisil solid phase extraction,five pyrethroids were well separated and detected by using menthol/water (78.5/21.5,V/V) as mobile phase.Under the optimum conditions,good linearities of five pyrethroids were obtained in the ranges of 0.5—50mg/L with detection limits of 0.1—0.15mg/L.By analyzing of the spiked tea sample,the recoveries of tea with different level content pyrethroids were between 71.4% and 104.4%,and relative standard deviation(n=5) were less than 10.0%.