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Interlaboratory comparison of limits of detectic in negative chemical ionization mass spectrometry
Author(s) -
Arbogast B.,
Budde W. L.,
Deinzer M.,
Dougherty R. C.,
Eichelberger J.,
Foltz R. D.,
Grimm C. C.,
Hites R. A.,
Sakashita C.,
Stemmler E.
Publication year - 1990
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.1210250403
Subject(s) - mass spectrometry , ion , ion source , ionization , electron ionization , chemistry , mass spectrum , analytical chemistry (journal) , detection limit , chemical ionization , electron , atomic physics , physics , nuclear physics , organic chemistry , chromatography
Data are presented on the limits of detection for a series of nine compounds in negative chemical ionization (NCI) mass spectra obtained in five different mass spectrometers: Finnigan 4000 with a 4500 ion source, Kratos MS‐80, Hewlett‐Packard 5985 and two Finnigan 4500s. The nine compounds undergo either resonance capture or dissociative capture of an electron at optimum energies ranging from 0.0 to 1.1 eV. The limits of detection generally increased with increasing optimum electron energy. The limit of detection as a function of optimum electron capture energy is expected to provide information about the electron energy distribution in the ion sources. The data showed scatter within and between instruments. The scatter is believed to be due primarily to reactions with low levels of adventitious gases such as oxygen in the ion source. The data also suggested wide variations in electron energies between the instruments. The variation in the electron energy distribution is thought to have been caused by variations in the ion optical fields within the instruments. These results suggest that the requirements for reproducibility in NCI mass spectra at the limit of detection are rigorous control of trace gases in the ion source, control of the electric fields within the source including ion optical fields that penetrate the source aperture control of pressure, temperature and other factors that influence NCI mass spectra.