Determination of lambda-cyhalothrin residue in tea and soil using gas chromatography
气相色谱法测定茶叶及土壤中的高效氯氟氰菊酯残留量

A gas chromatographic (GC) method was established for the determination of lambda-cyhalothrin residue in tea and soil. Tea and soil samples were extracted with hexane, separated by capillary column and determined by gas chromatography-electron capture detector (GC-ECD). The average recoveries of lambda-cyhalothrin in tea and soil were 89.0%-94.1% and 89.8%-94.7% , respectively at the spiking levels of 0.02 to 2.00 mg/kg. The corresponding relative standard deviations (RSDs, n=5) were 3.0%-4.9% and 2.5%-4.2%, respectively. The limit of detection (S/N=3) was 0.002 mg/kg for lambda-cyhalothrin. The degradations of 2.5% lambda-cyhalothrin microemulsion in tea and soil in Changsha, Hunan were investigated and the degradation equations were y=3.1996e-0.3394x and y=0.1224e-0.1036x with the correlation coefficients of 0.9956 and 0.9247, respectively. The half-lives of lambda-cyhalothrin in tea and soil were 2.04 days and 6.69 days, respectively.