14种二苯醚类除草剂的质谱裂解行为规律  

Mass Spectrometric Cleavage Behavior of 14 Diphenyl Ether Herbicides

作　　者：连增维 鄢勤 胡彧娴[1] 赖添财[1] Lian Zengwei;Yan Qin;Hu Yuxian;Lai Tiancai(Zhangzhou Agricultural Test and Inspection Center,Zhangzhou Fujian 363000,China;Plant Protection and Quarantine Station of Lezhi County,Ziyang Sichuan 641500,China)

机构地区：[1]漳州市农业检验监测中心,福建漳州363000 [2]四川省资阳市乐至县农业农村局植保植检站,四川资阳641500

出　　处：《农药科学与管理》2024年第10期43-52,65,共11页Pesticide Science and Administration

摘　　要：通过分析14种二苯醚类除草剂(Diphenyl Ether Herbicides,DpEH)在EI源中的质谱图,对DpEH裂解生成的特征碎片离子及其断裂方式做了比较研究。DpEH的质谱裂解有以下规律:(1)游离基中心定域在二苯醚的氧原子上,可发生四元环过渡态的氢重排反应或i-断裂;(2)游离基中心定域在硝基的氮原子上,可发生i-断裂,失去二氧化氮自由基或者在加热状态下形成激发态,发生α-断裂,失去一氧化氮自由基;(3)苯环上带正电荷且有氯取代基的离子,可生成碎片离子m/z[M-35]和m/z[M-36];(4)其他如含有三氟甲基的易失去氟自由基,含有羧基的易失去中性分子CO。借助DpEH在质谱中的特征碎片离子和特征断裂规律可对此类除草剂作出鉴别和确认,并提供定量定性离子选择的理论基础。The characteristic fragment ions and cleavage patterns of 14 Diphenyl Ether Herbicides(DpEH)were comparatively studied by analyzing their mass spectra in EI source.The mass spectrometry fragmentation of DpEH usually followed the following pattern:(1)Hydrogen rearrangement or i-breakage occurs when the free radical is localized at the oxygen atom of Diphenyl Ether;(2)i-breakage occurs when the free radical is localized at the oxygen atom of nitro,resulting in the loss of NO2,or it can form an excited state upon heating,leading toα-breakage and the loss of NO;(3)The ions with positive charge and chlorine substituent in the benzene ring generate fragment ions at m/z[M-36]and m/z[M-35];(4)Others ions easily lose fluorine radical in trifluoromethyl groups or CO in carboxyl group.The identification and confirmation of DpEH in EI source can be achieved with the aid of characteristic fragment ions and cleavage patterns,providing a theoretical basis for quantitative and qualitative ion selection.

关 键 词：二苯醚类除草剂 质谱裂解规律 电子轰击离子源(EI) 

分 类 号：S482.4[农业科学—农药学]