GC-MS Determination of Pyrethroid Pesticides in Water Samples with Hollow Fibrous Membranes-Liquid Phase Micro-extraction

GC-MS was used in the determination of pyrethroid pesticides,including tetramethrin,fenpropathrin and permethrin in water samples.The sample was extracted by hollow fibrous membranes-liquid phase micro-extraction method (HFM-LPME) with methylbenzene as extraction solvent.The extraction was carried out under magnetic stirring for 20 min,at the rate of 600 r·min-1 and at the temperature of 35 ℃.Under the optimal extraction conditions,enrichment factors for tetramethrin,fenpropathrin and permethrin obtained were 292,63 and 76,respectively.Linear relationships between values of response signal and mass concentration of the 3 pyrethroid pesticides were obtained in definite ranges,with detection limits (3S/N) less than 0.5 μg·L-1.Tests for recovery and precision were made and values of recovery and RSD′s (n=6) found were in the ranges of 92.4%-98.0% and 1.9%-8.6% respectively.