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Cluster ion structures formed by positive and negative chemical ionization of lactic and other hydroxyacids
Author(s) -
Li Zhongmin,
Kruger T. L.,
Cooks R. G.
Publication year - 1982
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210171011
Subject(s) - mass spectrum , chemistry , ion , ionization , chemical ionization , cluster (spacecraft) , covalent bond , electron ionization , hydrogen bond , mass spectrometry , cationic polymerization , molecule , analytical chemistry (journal) , organic chemistry , chromatography , computer science , programming language
Both positive ion and negative ion chemical ionization mass spectra of hydroxycarboxylic acids (hydroxyethanoic acid, 3‐hydroxypropanic acid, 2‐hydroxypropanoic acid and 1‐phenyl‐1‐hydroxyethanoic acid) show intense oligomeric ions when the samples are evaporated into a chemical ionization source. The observation of oligomeric anionic and cationic species is unusual, and the parallel behavior observed between the positive and negative ion mass spectra is striking. These results are explicable in terms of evaporation of oligomers and their dehydration products from the hot probe, although gas phase clustering reactions of singly charged ions are not excluded. Hydrogen bonding and dehydration provide bonding within each cluster. The structures of the ions have been confirmed by recording the collision induced dissociations of individual cluster ions via their mass analyzed ion kinetic energy spectra. Temperature dependence of the chemical ionization mass spectra provides a method for distinguishing hydrogen bonding from covalent bonding and gives further structural information on the cluster ions.