样品(10g)先后用20 mL及15 mL乙腈超声波提取118种农药残留,经盐析并离心除水液液分配,所得提取液经40 ℃旋转蒸干,残渣溶于乙腈-甲苯(3+1)混合溶液5 mL中,溶液经Carb/PSA双层固相萃取小柱净化,淋出液蒸至近干并溶于丙酮-正己烷(1+1)混合溶液1.0 mL中,供气相色谱-质谱分析。分析中采用HP-5MS毛细管色谱柱及EI离子源和选择离子扫描方式,外标法定量。方法的测定下限(10S/N)在0.01~0.031 mg·kg-1之间,在加标水平为0.05 mg·kg-1时,方法回收率为67%~124%,相对标准偏差(n=5)小于12.2%。

Residual amounts of 118 pesticides in sample (10 g) of grape wine were extracted with 20 mL and 15 mL of acetonitrile in succession, centrifuged and the supernatants were collected. After evaporation to dryness at 40 ℃ in a rotary evaporator, the residue was dissolved in 5 mL of a mixture of acetonitrile and toluene (3+1). The solution was purified on the Carb/PSA double layer SPE column. The eluate obtained was evaporated to near dryness. The residue was taken up with 1.0 mL of a mixture of acetone and n-hexane (1+1), and the solution was used for GC-MS analysis, with HP-5MS capillary chromatographic column, and EI as well as SIM in MS determination. An external standard was used for quantitative analysis. Values of lower limit of determination (10S/N) found were ranged from 0.010 to 0.031 mg·kg-1 and values of recovery found by standard addition method were in the range of 67%-124% with RSD′s (n=5) less than 12.2%.