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Formation of [M + 15] + ions from aromatic aldehydes by use of methanol: in‐source aldolization reaction in electrospray ionization mass spectrometry
Author(s) -
Wang Lin,
Chai Yunfeng,
Tu Peijun,
Sun Cuirong,
Pan Yuanjiang
Publication year - 2011
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1994
Subject(s) - chemistry , mass spectrometry , electrospray ionization , extractive electrospray ionization , methanol , ion , electrospray , selected reaction monitoring , ion source , chromatography , direct electron ionization liquid chromatography–mass spectrometry interface , sample preparation in mass spectrometry , ionization , organic chemistry , chemical ionization , tandem mass spectrometry
Unexpected [M + 15] + ions were formed during the analysis of aromatic aldehydes by use of methanol in positive‐ion electrospray ionization mass spectrometry. Aromatic aldehydes with electron‐withdrawing groups or electron‐donating groups were all tested to make sure the universality. All the aromatic aldehydes studied with methanol as the solvent could generate [M + 15] + ion, and for most of them, the [M + 15] + ion was more intense than the [M + H] + ion. Deuterium‐labeling experiment, high‐performance liquid chromatography–MS experiment, collision‐induced dissociation experiment, and theoretical calculations were performed to identify the formation of [M + 15] + ion. The proposed reaction mechanism is a gas‐phase aldol reaction between protonated aromatic aldehydes and methanol occurring in electrospray source. Understanding and using this unique gas‐phase ion/molecule reaction can indeed offer a novel and fast approach for the direct identification of aromatic aldehydes. Copyright © 2011 John Wiley & Sons, Ltd.