农药快速检测技术提取效率对比研究

Comparison on the Extract Efficiency Between Two Fast Detection Methods for the Pesticides Residue in Vegetables

对现存农药快速检测技术中存在的农药提取效率问题进行了研究。将6种农药混合标样添加到4种蔬菜表面上,间隔2h或5h后分别采用20%甲醇水溶液或0.1mol·L-1磷酸缓冲液浸泡,在振荡器上进行模拟表面冲洗提取试验。结果表明,当添加农药后的时间间隔为2h时,添加的农药主要呈简单的吸附持留在蔬菜的表面,80%～98%的添加农药可以被提取出来,随着时间间隔的延长(至5h),采用表面冲洗法的农药提取效率急剧下降,大部分农药的提取效率仅为20%～60%,简单的表面冲洗法在实际应用中很难将蔬菜中残留的农药提取出来,因而不能满足对农药残留快速检测的要求。

Surface rinsing method was broadly used in fast detection for pesticides residue in vegetables. The extracting efficiency by surface rinsing method was determined. Four kinds of vegetables were spiked with standard solution of 6 pesticides mixture to obtain spiked levels of 0.5 mg·kg^-1 or 1.0 mg·kg^-1, respectively. These samples were extracted with 20% methanol-water solution or 0.1 mg·kg^-1 phosphate butter solution （PBS） with mechanical shaker after placed at air temperature for 2 hours or 5 hours, respectively. The extracted pesticides were detected by gas chromatography. The results showed that more than 80% pesticides could be extracted after placed in air 2 hours since the pesticides were mainly absorbed on vegetables, but after 5 hours keeping in air, the extract efficiency dropped rapidly to 20%-60%. This indicated that simply surface rinsing method could not extract pesticides efficiently from vegetable samples.