Objective To study the cleavage pathways of 3-aminobenzoic acid ethyl ester by electrospray ionization mass spectrometry (ESI-MS/MS) in the positive mode. Methods The quasi-molecular ion [M+H] of 3-aminobenzoic acid ethyl ester was obtained by ESI, and the MS2 spectrum of quasi-molecular ion [M H] ion were obtained from collision-induced dissociation (CID). Results There were three main fragment ions of quasi-molecular ion [M H] with CID that were m/z 138, m/z 94, m/z 77. The cleavage pathways information of [M H] ion were obtained by analyzing the MS2 spectrum of [M H] ion. It was found that quasi-molecular ion [M H] mainly fractured through ethoxyl group at the C1 of benzene ring, and lost CH2=CH2 with generated fragment ion m/z 138. A part of fragment ion m/z 138 continuously lost CO2 at the C1 of benzene ring with generated fragment ion m/z 94. Then a part of fragment ion m/z 94 lost NH3 at the C3 of benzene ring with generated characteristic fragment ion m/z 77. Conclusion These cleavage rules presented here can provide a technical support for metabolites’ identification of 3-aminobenzoic acid ethyl ester in aquatic products.
标题：3-氨基苯甲酸乙酯的电喷雾正离子质谱裂解规律
英文标题：The cleavage pathways of 3-aminobenzoic acid ethyl ester by positive elec-trospray ionization mass spectrometry
