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目的采用电喷雾电离串联质谱(ESI-MS/MS),对3-氨基苯甲酸乙酯在正离子模式下的裂解途径进行分析研究。方法通过ESI电离产生准分子离子[M+H]+,并对[M+H]+进行碰撞诱导解离(CID)获得3-氨基苯甲酸乙酯的二级质谱图。结果在CID模式下,3-氨基苯甲酸乙酯主要产生m/z 138、m/z 94和m/z 77三个碎片离子。通过解析3-氨基苯甲酸乙酯二级质谱图得到其裂解途径信息:3-氨基苯甲酸乙酯首先断裂苯环C1位支链上的乙氧基丢失一个乙烯生成特征碎片离子m/z 138,然后断裂苯环C1位支链上酯基丢失一个CO2生成特征碎片离子m/z 94,继续断裂C3位上C-N键丢失一个NH3并生成特征碎片离子m/z 77。结论 本研究所提出的3-氨基苯甲酸乙酯的电喷雾质谱裂解规律,为其在水产品体内代谢物质的鉴别提供参考依据。
OBJECTIVE To study the cleavage pathway of ethyl 3-aminobenzoate in positive mode by electrospray ionization tandem mass spectrometry (ESI-MS / MS). Methods The second order MS spectra of ethyl 3-aminobenzoate were obtained by ionization of ESI to generate quasi-molecular ion [M + H] + and collision-induced dissociation (CID) of [M + H] +. Results In CID mode, ethyl 3-aminobenzoate produced mainly three fragment ions of m / z 138, m / z 94 and m / z 77. By analyzing the mass spectrum of ethyl 3-aminobenzoate, the cleavage pathway information is obtained: ethyl 3-aminobenzoate first breaks the ethoxy group at the C1-position of benzene ring and loses one ethylene to generate characteristic fragment ion m / z 138 , Then cleavage of the C1 on the C1 branch of the benzene ring results in the loss of a CO2 fragment to generate the characteristic fragment ion m / z 94, continuing the cleavage of the CN bond on the C3 position to lose a NH3 and generate characteristic fragment ions m / z 77. CONCLUSION The electrospray ionization mass spectrometry of ethyl 3-aminobenzoate, which is proposed in this study, provides a reference for the identification of metabolites in aquatic products.