Premium
Charge‐exchange reactions with water in the detection of perfluorocarbons by thermospray liquid chromatography/mass spectrometry
Author(s) -
Huang S. K.,
Klein D. H.,
McLoughlin M.
Publication year - 1989
Publication title -
biomedical and environmental mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0887-6134
DOI - 10.1002/bms.1200180204
Subject(s) - thermospray , chemistry , mass spectrometry , decalin , chemical ionization , direct electron ionization liquid chromatography–mass spectrometry interface , ionization , chromatography , ion , cyclohexane , analytical chemistry (journal) , selected reaction monitoring , organic chemistry , tandem mass spectrometry , catalysis
Perfluorocarbons (PFCs) can be detected by thermospray liquid chromatography/mass spectrometry (LC/MS) only when the system is operated in the negative ion mode with filament on and some water entering the thermospray source. A new mechanism for PFC ionization is proposed, based on studies of LC/MS detection of the perfluorinated forms of cyclohexane, methyl and dimethyl cyclohexane, decalin, 1‐methyl decalin and toluene. The ion evaporation mechanism of Dodd, involving pre‐ionization of PFCs in the presence of aqueous NH 4 OAc, is not operative, nor is chemical ionization of PFCs by the reagent ions as in true thermospray LC/MS. Instead, PFC ionization is attributable to the negative ions formed from the water in the source; these ions undergo prompt charge‐exchange reactions with the more electronegative PFCs to form structure‐retaining PFC ions.