固相萃取-气相色谱法快速测定大葱中有机磷农药残留量

RAPID DETERMINATION OF RESIDUAL ORGANOPHOSPHORUS PESTICIDES IN WELSH ONION BY SOLID-PHASE EXTRACTION-GAS CHROMATOGRAPHY

研究建立了高含量基体干扰大葱样品中有机磷农药残留量分析方法.采用乙腈水提取,有机相盐析后经硅胶柱净化,以双毛细柱GC-FPD定性定量,该方法对8种有机磷农药的添加回收率为60%～130%,RSD＜18%,检出限为0.02～0.05 mg·kg-1,符合残留分析要求.

Gas chromatography hyphenated with solid-phase extraction was applied to the rapid determination of 8 residual organophosphorus pesticides （Opp＇s） in welsh onion. The onion sample （25 g） was extracted with a mixture containing 50 mL of acetonitrile and 10 mL of sat＇d NaCl water solution. The extract was filtered and salted out with 6 g of NaCl by shaking vigorously for 3 min in a separatory funnel. 10. 0 mL of the organic phase was evaporated （at 40 ℃） to dryness, and the residue was taken up with 1.0 mL of n-hexane, and purified by SPE on silica gel column （Accu Bond Ⅱ silica cartridges）. The Opp＇ s on the column was eluted with acetone-n-hexane （1＋1） mixture and 15 mL of the eluate was taken and dried by blowing with nitrogen, n-Hexane （1.0 mL） was used to dissolved the residue and the solution was used for GC determination. Two capillary columns （HP 5 and DB1701） with different polarity were used in the GC identification and determination, and two flame photometric detectors were used. Recoveries for the 80pp＇s were tested by the standard addition method and the results obtained were in the range of 60%-130%. RSD＇s found were less than 18%. Detection limits were in the range of 0. 02-0. 05 mg · kg^- 1.