Determination of 7 pyrethroids residues in aquatic product by gas chromatography

Gas chromatography with electron capture detection method was developed for the determination of 7 pyrethroids residues in aquatic products.Pyrethroids were extracted with cyclohexane and ethylacetate(1∶1,V/V)and lipids were removed with petroleum ether.Cleanup was performed on a LC-Florisil column.The working curves for the pyrethroids were linear(r≥0.992) in the range of 1 to 100 μg/L.When spiked with 5,10 and 20 μg/kg of pyrethroids,the average recoveries were 70.0%-114.8% and the intra-day RSD(n=5) were 1.2%-9.8% and the inter-day RSD(n=3) were 3.8%-11.2%.The detection limit as estimated by 2 times signal to noise method for bifenthrin,fenpropathrin,lambda-cyhalothrin,permethrin was 1 μg/kg and for permethrin,fenvalerate,deltamethrin was 2 μg/kg respectively.