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, lambdacyhalothrin, permethrin was 1 μg/kg and for permethrin, fenvalerate, deltamethrin was 2 μg/kg respectively.