摘要
在pH大于12的条件下使水样中的氯代除草剂全部水解为盐,用正己烷和甲基叔丁基醚混合溶剂提取有机杂质,再在酸性条件下经5mL甲基叔丁基醚提取,重氮甲烷甲基衍生化30min后用带微电子捕获检测器的毛细管气相色谱分析,以4,4’-二溴八氟联苯为内标物进行定量。茅草枯、麦草威、2,4-D、五氯苯酚的质量浓度分别在5.0—500、1.0~200、5.0~500、0.5~100ug/L范围内与色谱峰面积呈良好的线性关系(r=0.9945~0.9980),检出限分别为1.0、0.5、1.0、0.1ug/L。用该法测定南京玄武湖水样中的茅草枯,其质量浓度为7.1ug/L,4种被测组分在高、中和低添加水平下的回收率分别为102%~105%、96%-110%、87%-109%。同时建立了一种生产重氮甲烷的新原料——N-亚硝基-N-甲基脲的简易方法。
Aqueous sample of chlorinated acid herbicides was hydrolyzed to salts under pH more than 12 and cleaned up by hexane - MtBE mixture, then acidified and extracted with 5 mL methyl tert-bu- tyl ether(MtBE). The chlorinated acid herbicides were derivatized by diazomethane for 30 rain. The target methyl esters were determined by capillary column gas chromatography with u-ECD. Quantitative analysis was carried out by using 4, 4'-dibromooctafluorobiphenyl as an internal standard. A good linearity(r =0. 994 5 -0. 998 0) was obtained in the range of 5.0 -500, 1.0 -200, 5.0 -500 and 0. 5 - 100 ug/L for dalapon, dicamba, 2, 4-D and pentachlorophenol, respectively. The detection limits were 1.0, 0. 5, 1.0 and 0. 1 ug/L, respectively. The concentration of dalapon in Nanjing Xuanwu Lake samples was detected to be 7.1 ug/L. And fortified recoveries were 102% - 105% , 96% -110% , 87% -109% for the four analytes at high, middle and low fortified levels, respectively. An easy way was also established to synthesize the N-methyl-N-nitroso-urea which was used to generate the diazomethane. The method could be used to determinate many chlorinated acid herbicides with high sensitivity, broad linear range, and minor environment pollution.
出处
《分析测试学报》
CAS
CSCD
北大核心
2009年第7期829-833,共5页
Journal of Instrumental Analysis
基金
国家环境标准制订资助项目(925)
关键词
氯代酸除草剂
气相色谱
甲基衍生化
微萃取
chlorinated acid herbicide
gas chromatography
methyl derivatization
microextraction