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Ammonia and methane chemical ionization mass spectra of acid and carbamate pesticides using direct supercritical fluid injection
Author(s) -
Kalinoski Henry T.,
Wright Bob W.,
Smith Richard D.
Publication year - 1986
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.1200130107
Subject(s) - chemical ionization , chemistry , mass spectrum , supercritical fluid , mass spectrometry , ion source , methane , supercritical fluid chromatography , chromatography , ammonia , ionization , gas chromatography , analytical chemistry (journal) , atmospheric pressure chemical ionization , ion , organic chemistry
The ammonia and methane chemical ionization mass spectra of several carbamate and acid pesticides were obtained utilizing capillary supercritical fluid chromatography (SFC) for introduction. These compounds are generally not amenable to gas chromatography and the supercritical fluid method allows low‐temperature separations (using carbon dioxide or nitrous oxide as mobile phases) with highly selective chemical ionization mass spectrometric detection for analysis. Ionization with ammonia produces primarily ammonium adduct ions, [M + 18] + , and protonated molecules, [M + 1] + , for all compounds. More energetic methane chemical ionization produces spectra containing fragment ions characteristic of the pesticide structure. All compounds were analysed under similar chromatographic conditions, with optimization for individual compounds minimized, and detection limits were in the picogram range. Analysis time for all compounds was under five minutes and no mobile phase interferences or thermal degradation was noted.