磷酸、膦酸酯类农药的质谱裂解规律研究

Study on Fragmentation Pattern in Mass Spectrum for Phosphate and Phosphonate Pesticides

在对23种磷酸、膦酸酯类农药及其氧化物的质谱数据进行归纳整理的基础上,明确了这类农药质谱裂解规律。结果表明:电子轰击离子化条件下,磷酸、膦酸酯类农药分子极易裂解,且分子离子峰较弱。发现C_2H_6O_3P^+(m/z109)是其最具代表性的特征碎片离子。磷酸酯类农药裂解规律是二甲氧基磷酸酯P-0键易发生a断裂,生成m/z 109特征碎片离子。二乙氧基磷酸酯易脱去中性碎片C_2H_4,形成m/z81的特征离子。R'含有烯烃结构,易产生m/z127的特征碎片离子。膦酸酯类农药裂解规律与磷酸酯类似,特征性弱,膦键容易发生a断裂。选定了磷酸、膦酸酯类农药在质谱分析中常见的碎片离子,为农药残留筛查、确证分析提供参考。

By summarizing and interpreting mass spectrometry data of 23 phosphoric acids,phosphonates and theiroxides,the fragmentation patterns of the above pesticides were made clear.The results showed the pesticides of phosphoric acid and phosphate ester are easily cracked under the electron impact ionization conditions,and the molecular ionic peaks are weak.The most representative characteristic fragment ions is C_2H_6O_3P+(m/z 109).The characteristic fragmentation pattern of phosphate ester pesticides is the-broken of P-0 bond into dimethoxy phosphate with m/z 109.The diethoxy phosphate can lost C_2H_4 easily,and generated m/z 81 characteristic ion.The R'contains olefin structure,so it is easy to produce the m/z 127 characteristic fragment ions.The fragmentation patterns of phosphonate and phosphate pesticides are similar with weak characteristics,and the phosphine bond is prone to-broken.At the same time,the common characteristic fragment ions of phosphate and phosphonate pesticides in mass spectrometry were selected toprovide an important reference for pesticide residue screening and identification analysis.