Premium
Complexes of bivalent metal cations in electrospray mass spectra of common organic compounds
Author(s) -
Bieńkowski Tomasz,
BrodzikBieńkowska Agnieszka,
Danikiewicz Witold
Publication year - 2002
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.322
Subject(s) - chemistry , mass spectrum , metal ions in aqueous solution , ion , metal , inorganic chemistry , qualitative inorganic analysis , mass spectrometry , molecule , electrospray ionization , alkali metal , organic chemistry , chromatography
Abstract In the standard electrospray ionization mass spectra of many common, low molecular mass organic compounds dissolved in methanol, peaks corresponding to ions with formula [3M + Met] 2+ (M = organic molecule, Met = bivalent metal cation) are observed, sometimes with significant abundances. The most common are ions containing Mg 2+ , Ca 2+ and Fe 2+ . Their presence can be easily rationalized on the basis of typical organic reaction work‐up procedures. The formation of [3M + Met] 2+ ions has been studied using N ‐FMOC‐proline methyl ester as a model organic ligand and Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Fe 2+ , Ni 2+ , Mn 2+ , Co 2+ and Zn 2+ chlorides or acetates as the sources of bivalent cation. It was found that all ions studied form [3M + Met] 2+ complexes with N ‐FMOC‐proline methyl ester, some of them at very low concentrations. Transition metal cations generally show higher complexation activity in comparison with alkaline earth metal cations. They are also more specific in the formation of [3M + Met] 2+ complexes. In the case of alkaline earth metal cations [2M + Met] 2+ and [4M + Met] 2+ complex ions are also observed. It has been found that [3M + Met] 2+ complex ions undergo specific fragmentation at relatively low energy, yielding fluorenylmethyl cation as a major product. [M + Na] + ions are much more stable and their fragmentation is not as specific. Copyright © 2002 John Wiley & Sons, Ltd.