Two competing ionization processes in ESI-MS analysis of N-(1, 3-diphenylallyl)benzenamines: formation of the unusual [M−H]+ ion versus the regular [M+H]+ ion. Issue 3 (June 2018)

• Record Type: Journal Article
• Authors: Fang, Liwen; Dong, Cheng; Guo, Cheng; Xu, Jianxing; Liu, Qiaoling; Qu, Zhirong; Jiang, Kezhi
• Is Part Of: European journal of mass spectrometry. Volume 24:Issue 3(2018)
• Page Start: 251
• Page End: 260
• Publication Date: 2018-06
• Subjects: N-(1 -- 3-diphenylallyl)benzenamine -- [M−H]+ -- electrospray ionization mass spectrometry -- two competing ionization processes; Mass spectrometry -- Periodicals; Mass Spectrometry; Mass spectrometry; Periodicals; Periodicals; 543.6505
• DOI: 10.1177/1469066717717228
• Languages: English
• ISSNs: 1469-0667

Abstract

A series of N -(1, 3-diphenylallyl)benzenamine derivatives (M) were investigated by electrospray ionization mass spectrometry in the positive-ion mode. Both the anomalous [M−H] + and the regular [M+H] + were observed in the ESI mass spectra. The occurrence of [M−H] + has been supported by accurate mass spectrometry, liquid chromatography mass spectrometry, and tandem mass spectrometry analysis. Calculation results indicated that formation of [M−H] + is attributed to the ion-molecule reaction of M with the protonated ESI solvent molecule (e.g. CH3 OH2 + ) via hydride abstraction from a tertiary Csp3 −H. The competing ionization processes leading to [M−H] + or [M+H] + were significantly affected by the concentration of formic acid in the electrospray ionization solvent and the proton affinity of the N atom.