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Silver cationization of thia fatty acids and esters in laser desorption/ionization time‐of‐flight mass spectrometry
Author(s) -
Owega Sandy,
Lai Edward P. C.
Publication year - 1999
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/(sici)1096-9888(199908)34:8<872::aid-jms842>3.0.co;2-f
Subject(s) - chemistry , mass spectrometry , desorption , time of flight mass spectrometry , substrate (aquarium) , analytical chemistry (journal) , chromatography , ionization , organic chemistry , ion , adsorption , oceanography , geology
A laser desorption/ionization (LDI) time‐of‐flight mass spectrometric (TOF‐MS) technique was used for the molecular mass analysis of thia fatty acids and esters, samples without appreciable light absorption at the laser wavelength. After a sample overlayer is deposited by solvent evaporation on a thin silver film substrate, it is subjected to 355 or 532 nm Nd : YAG laser irradiation. Photoablation of the Ag film substrate occurs with sufficient laser fluence, producing silver cluster cations, which can react with the desorbed thia fatty acid or ester molecules in the gas phase. Silver cation attachment of thia fatty esters may produce a silver‐cationized analyte and fragments of structural diagnostic value, whereas thia fatty acids would not. With oxygen(s) present on the sulfur in sulfoxy fatty acids and esters, a silver‐cationized analyte and additional fragments are produced. Formation of these fragments is consistent with charge‐remote mechanisms through simple cleavage and rearrangement pathways. The structural reactivity of these compounds with ablated silver cations is hence comprehensively analyzed. Copyright © 1999 John Wiley & Sons, Ltd.