提出了气相色谱-串联质谱法测定罗非鱼中7种拟除虫菊酯类农药(联苯菊酯、甲氰菊酯、三氟氯氰菊酯、氯菊酯、氯氰菊酯、氰戊菊酯和溴氰菊酯)残留量的方法。样品以环己烷-乙酸乙酯(1+1)混合液为萃取剂,经加速溶剂萃取仪提取后,经Florisil固相萃取小柱净化后,用丙酮-正己烷(1+9)混合液淋洗,洗脱液于45 ℃水浴氮吹近干后用正己烷定容至1 mL,通过TR-5MS毛细管色谱柱分离,采用电子轰击离子源选择反应监测模式进行质谱测定。7种拟除虫菊酯类农药的检出限(3S/N)在0.20~2.1 μg·kg-1之间。以空白罗非鱼样品为基体,加入标准溶液进行回收试验,测得回收率在57.9%~107%之间,测定值的相对标准偏差(n=6)均小于12.0%。

GC-MS/MS was applied to the determination of residual amounts of 7 pyrethroid pesticides (i.e., bifenthrin, fenpropathrin, cyhalothrin, permethrin, cypermethrin, fenvalerate and deltamethrin) in tilapia. The sample was extracted with a mixture of cyclohexane-ethyl acetate (1+1) by accelerated solvent extraction, and the extract was purified on Florisil solid phase extraction (SPE) column. The 7 pyrethroid pesticides were eluted from the SPE column with a mixture of acetone-n-hexane (1+9) and the eluate was evaporated to near dryness by N2-blowing on a water bath at 45 ℃. The residue obtained was dissolved and made up to 1.0 mL with n-hexane, which was used for GC-MS/MS analysis. TR-5MS capillary chromatographic column was used for separation, and the selected reaction monitoring (SRM) with electron impact ionization source was adopted in MS. Values of detection limit of 7 pyrethroid pesticides were found in the range of 0.20-2.1 μg·kg-1. On the base of blank sample of tilapia, test for recovery was made by standard addition method, values of recovery found were in the range of 57.9%-107%, with RSD′s (n=6) less than 12.0%.