黄瓜样品经乙腈超声波提取后,用活性炭固相萃取小柱净化,用乙腈洗脱,将洗脱液旋转蒸发至近干,用乙腈-水(1+1)溶液1.0 mL溶解测定。采用Hypersil GOLD C18色谱柱(2.0 mm×150 mm,3 μm)分离,用不同比例配成的10 mmol·L-1乙酸铵溶液(含甲酸φ 0.1%)和乙腈为流动相梯度洗脱。质谱测定中采用正离子电离方式,选择离子监测模式。霜霉威的质量浓度在1.02~1 020 μg·L-1范围内与峰面积呈线性关系,测定下限(10S/N)为0.2 μg·kg-1。用标准加入法做回收试验,测得回收率在88%~96%之间,测定值的相对标准偏差(n=6)在4.7%~6.4%之间。

Sample of cucumber was extracted with acetonitrile, and the extract was purified by passing through the activated carbon SPE column and eluting with acetonitrile. The eluate was evaporated rotationally to near dryness, and made up its volume to 1.0 mL with acetonitrile-H2O (1+1) solution. Hypersil GOLD C18 (2.0 mm×150 mm, 3 μm) chromatographic column was used for separation, using the mixed solutions of 10 mmol·L-1 ammonium acetate (containing φ 0.1% formic acid) and acetonitrile in different ratios as mobile phase in the gradient elution. ESI with positive ionization mode and select ion monitoring mode was used in the MS/MS analysis. Linear relationship between values of peak area and mass concentration of propamocarb was found in the range of 1.02-1 020 μg·L-1, with lower limit of determination (10S/N) of 0.2 μg·kg-1. Test for recovery was made by standard addition method, giving values of recovery and RSD′s (n=6) in the ranges of 88%-96%and 4.7 %-6.4% respectively.