倍硫磷在新疆哈密瓜中的残留检测及其在土壤中的降解行为研究

Detection of fenthion residues in Hami melon and its degradation behavior in soils

采用气相色谱-质谱(GC-MS)技术检测分析新疆不同产地的哈密瓜及种植地环境样品(水样和土壤)中倍硫磷及代谢产物倍硫磷砜的残留量,样品经有机溶剂萃取,固相萃取柱净化,乙腈+甲苯洗脱,浓缩定容后检测。试验结果表明:在土壤、水样和哈密瓜样品中的平均添加回收率为82.3%~104.1%,相对标准偏差为1.3%~7.9%;在0.1~2.0 mg/L质量浓度范围内线性关系良好(r2>0.999)。通过对不同产地采集的样品进行测试发现,仅在土壤样品中检测出倍硫磷;考察倍硫磷在土壤中的降解规律发现,试验第35天,倍硫磷的降解率在光照条件下为91.1%,而在避光条件下为70.6%,光照条件可加速倍硫磷在土壤中的降解速率。该方法适用于环境样品(土、水)和哈密瓜中倍硫磷和倍硫磷砜残留量的检测,方法学结果均达到农药残留分析标准要求。

In this experiment,the residues of fenthion and its metabolite fenthion sulfone were detected and analyzed by gas chromatography-mass spectrometry(GC-MS)in Hami melons of different origins in Xinjiang and in environmental samples(water samples and soils)of the cultivation sites.The different samples were extracted with organic solvents,cleaned-up by a solid phase extraction(SPE)column,eluted with acetonitrile+toluene,and concentrated for detection.The average recoveries in soil,water and Hami melon samples ranged from 82.3%to 104.1%with the relative standard deviations(RSD)of 1.3%-7.9%,and the linearity was good in the concentration of 0.1-2.0 mg/L(r2>0.999).It was found that only in the soil samples,fenthion residues were present.Examining the degradation pattern of fenthion in soil,by the established method,the degradation rate of fenthion on the 35th day after the test was 91.1%under light condition and 70.6%under light-avoidance condition,and the light condition could accelerate the degradation rate of fenthion in soil.The method established in this study was suitable for the determination of fenthion and fenthion sulfone residues in environmental samples(soil and water)and Hami melon,and the methodological results met the standards for pesticide residue analysis.