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目的建立固相萃取-气相色谱法测定小麦籽粒中吡氟酰草胺、氟噻草胺和呋草酮3种农药的残留量。方法粉碎的小麦籽粒样品经丙酮浸泡提取,蒸出丙酮后用二氯甲烷萃取并浓缩,用石油醚置换二氯甲烷后,经Florisil-SPE小柱净化,采用气相色谱仪HP-5(30 m×0.25 mm×0.25μm)色谱柱分离,电子捕获检测器检测,以外标法定量。结果吡氟酰草胺、氟噻草胺和呋草酮3种农药可有效分离,线性范围分别为0.025~1.0、0.005~0.2和0.05~2.0μg/mL,标准曲线方程分别为Y=22319X+79.149,Y=56242X-26.653和Y=3285.1X-11.295,相关系数均大于0.999。最低检出浓度分别为0.01、0.005、0.02 mg/kg,平均回收率为77.0%~106.3%,相对标准偏差2.3%~10.6%。结论该方法简便、快速、准确、重现性好,能够在同时检测吡氟酰草胺、氟噻草胺和呋草酮3种除草剂成分。
OBJECTIVE To establish a solid phase extraction-gas chromatographic method for the determination of three pesticides residues of flufenacet, flufenacet and furfurone in wheat grains. Methods Pulverized wheat samples were extracted with acetone, acetone was distilled off, extracted with dichloromethane and concentrated. After replacing dichloromethane with petroleum ether, the samples were purified by Florisil-SPE cartridge and analyzed by gas chromatography HP-5 (30 m × 0.25 mm × 0.25μm) column separation, electron capture detector detection, external standard method. Results The three pesticides of difloxacin, flufenacet and furfural could be effectively separated with the linear range of 0.025-1.0,0.005-0.2 and 0.05-2.0μg / mL respectively. The standard curve equations were Y = 22319X + 79.149, Y = 56242X-26.653 and Y = 3285.1X-11.295, the correlation coefficients are all greater than 0.999. The minimum detectable concentrations were 0.01, 0.005 and 0.02 mg / kg, respectively. The average recoveries were 77.0% -106.3% with relative standard deviations of 2.3% -10.6%. Conclusion The method is simple, rapid, accurate and reproducible. It can simultaneously detect the three herbicides of difloxacin, flufenacet and furosemide.