苯甲酸型芳香小分子的电喷雾多级质谱裂解规律

Fragmentation Study of Benzoic Acid Type Small Aromatic Molecules by ESI-MS^n

采用电喷雾多级质谱技术研究11种苯甲酸型芳香小分子化合物的裂解途径,解释苯环上取代基的一般裂解规律。对所有的化合物均同时采用正离子和负离子检测模式进行扫描,取[M+H]^+和[M-H]^-准分子离子峰进行多级碰撞诱导解离,通过分析母离子和碎片离子的关系来确定这些化合物的裂解途径。研究结果表明,苯甲酸型芳香小分子优先断裂脱去主要的官能团,再断裂苯环上的羟基和甲氧基,最后是苯环的裂解。

Eleven benzoic acid type small aromatic molecules were introduced to analyze the fragmentation pathways by electrospray ionization tandem mass spectrometry(ESI-MSn),aiming at the investigation of fragmentation of functional groups and substituted groups in benzene ring.Base on the ESI-MSn(n=1-4)analysis,the fragmentation patterns of all compounds were proposed in positive-ion and negative-ion modes.The[M+H]^+and[M-H]^-ions were readily observed in conventional single-stage mass spectrometry,which were selected for collision-induced dissociation(CID)to produce daughter ions.The ESI-MSn fragmentation pathways of small aromatic molecules were comprehensively elucidated,which indicated the sequence of cleavages of functional groups,followed by neutral losses of substituted groups and ring-reducing reaction in benzene ring.