重氮甲烷衍生气相色谱-质谱法检测地下水中17种酸性除草剂

通过水体中酸性除草剂存在形态的改变,衍生试剂的选择及定量离子的确定,建立了重氮甲烷衍生气相色谱-质谱法检测水中卤代酸类、苯酚类、氮硫杂环类酸性除草剂的方法。重氮甲烷与酸性除草剂发生衍生反应,生成易于气相色谱-质谱测定的酯类化合物,反应条件温和,副产物少。采用自行设计制造的重氮甲烷发生装置,有效控制了二甲基亚硝基苯磺酰胺的反应用量,减少了有害气体的排放。对重氮甲烷连续鼓泡法和间断鼓泡法进行了试验对比。方法检出限为4.95~9.80 ng/L,精密度(RSD,n=7)为1.7%~7.9%,对不同添加水平的回收率进行对比,回收率控制在67.5%~126.3%。

Detection of 17 Acid Herbicide Residues in Groundwater by Gas Chromatography-Mass Spectrometry with Diazomethane Derivation

A method for the determination of acid herbicide residues,including halogenated acid herbicides,phenols,nitrogen and sulfur-containing heterocyclic herbicides,was established by changing their existing forms,selection of the derivative reagents and gas chromatography-mass spectrometric(GC-MS) quantitative determination.Under mild reaction condition,the derivative reaction of diazomethane with acid herbicides occurred and produced ester compounds with little by-products,which could be easily detected by GC-MS.By adopting the self-designed diazomethane generating device,the dosage of reaction reagent of diazald was effectively controlled and the harmful gas release was reduced.Experimental comparison was also made between the continuous bubble method and the intermittent bubble method of diazomethane.The detection limits for the herbicides were 4.95~9.80 ng/L and the recovery for different adding levels was 67.5%～126.3% with precision of 1.7%～7.9%RSD(n=7).