二氯丙基酯化-气相色谱法分析葡萄叶中3种除草剂

目的建立葡萄叶中2甲4氯、2,4-滴和2,4-滴丙酸3种苯氧羧酸类除草剂的二氯丙基酯化-电子俘获检测气相色谱分析法。方法样品捣碎、添加内标2,4-二氯苯乙酸、酸化、用乙醚提取,提取液用液液分配法净化,净化后挥干有机溶液,用硫酸和1,3-二氯丙-2-醇进行酯化,生成的酯进行气相色谱分析。结果葡萄叶中2甲4氯、2,4-滴和2,4-滴丙酸的检测限分别为20ng/g、20ng/g和30ng/g,葡萄叶中除草剂浓度100~1000 ng/g成线性关系,空白葡萄叶中添加2甲4氯、2,4-滴和2,4-滴丙酸200ng/g的平均回收率分别为98.8%、101.3%和103.1%,回收率的变异系数分别为11.4%、11.0%和9.3%。结论本文方法检测被毒害的葡萄叶中3种除草剂是灵敏和准确的。

The analytical method of three phenoxyalkanoic acid herbicides in grape leaf by dichioropropyl esterification and gas chromatography

ObjectiveTo develop a analytical method of three phenoxyalkanoic acid herbicides,MCPA,2,4-D and dichlorprop,in grape leaf using dichloropropyl esterification and gas chromatography with electron-capture detection.MethodsSamples were pounded to pieces,added into internal standard 2,4-dichlorophenylacetic acid,acidified and extracted with ethyl ether.The extracts were cleaned up by liquid-liquid partition.The cleaned organic solutions were evaporated and the residues were dichloropropylated using sulfuric acid and 1,3-dichloropropan-2-ol.The formed esters were analysed by gas chromatography.ResultsThe detection limits of MCPA,2,4-D and dichlorprop in grape leaf were 20ng/g,20ng/g,and 30ng/g,respectively.The concentritions of herbicides in grape leaf were linear over the ranger 100~1000ng/ml.The average recoveries of MCPA,2,4-D and dichlorprop in spiked grape leaf at concentrition of 200ng/g were 98.8%,101.3% and 103.1% with the coefficients of variation 11.4%,11.0% and 9.3% respectively.ConclusionThis method is sensitive and accurate for determination of these three herbicides in poisoned grape leaf.