Reagent gases for G.C.-M.S. analyses

Jelus, Barbara L.; Munson, Burnaby; Fenselau, Catherine

doi:10.1002/bms.1200010203

Cited by 52 publications

(21 citation statements)

References 21 publications

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“…Jelus et al () using nitrogen/(CH 3 ) 4 Si mixtures under CI conditions failed to observe [M+73] + ions from dihydrocholesterol whose spectrum exhibited [M − TMS‐OH] + ions. Use of (CH 3 ) 3 SiOSi(CH 3 ) 3 also failed to produce [M+73] + ions from steroidal alcohols and the authors concluded that, for some classes of compounds, chemical ionization would not give the required ions even in the presence of the high‐pressure conditions of the experiment that should have provided collisional cooling and stabilization of the [M+73] + ions.…”

Section: Inter‐molecular Reactions Of Siliconium Ionsmentioning

confidence: 99%

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Harvey

Vouros

2019

Mass Spectrometry Reviews

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This review describes the mass spectral fragmentation of trimethylsilyl (TMS) and related alkylsilyl derivatives used for preparing samples for analysis, mainly by combined gas chromatography and mass spectrometry (GC/MS). The review is divided into three sections. The first section is concerned with the TMS derivatives themselves and describes fragmentation of derivatized alcohols, thiols, amines, ketones, carboxylic acids and bifunctional compounds such as hydroxy‐ and amino‐acids, halo acids and hydroxy ethers. More complex compounds such as glycerides, sphingolipids, carbohydrates, organic phosphates, phosphonates, steroids, vitamin D, cannabinoids, and prostaglandins are discussed next. The second section describes intermolecular reactions of siliconium ions such as the TMS cation and the third section discusses other alkylsilyl derivatives. Among these latter compounds are di‐ and trialkyl‐silyl derivatives, various substituted‐alkyldimethylsilyl derivatives such as the tert‐butyldimethylsilyl ethers, cyclic silyl derivatives, alkoxysilyl derivatives, and 3‐pyridylmethyldimethylsilyl esters used for double bond location in fatty acid spectra. © 2019 Wiley Periodicals, Inc. Mass Spec Rev 0000:1–107, 2019

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Section: Inter‐molecular Reactions Of Siliconium Ionsmentioning

confidence: 99%

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Harvey

Vouros

2019

Mass Spectrometry Reviews

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“…Neopentane produces similar positive CI spectra to isobutane and doubles the electron filament lifetime [20] but is many times more expensive than isobutane to obtain at high purity. Dilution of deleterious analytical gases, including isobutane with inert gases, has been performed for CI [29][30][31][32], but the experiments were not constructed for isobutane to directly interact with an analyte. In the present research, a reagent gas mixture of isobutane diluted in argon produces positive CI and EC-NCI spectra of equal or better quality to pure isobutane.…”

Section: Introductionmentioning

confidence: 99%

Isobutane Made Practical as a Reagent Gas for Chemical Ionization Mass Spectrometry

Newsome

Steinkamp

Giordano

2016

J. Am. Soc. Mass Spectrom.

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Abstract. As a reagent gas for positive-and negative-mode chemical ionization mass spectrometry (CI-MS), isobutane (i-C 4 H 10 ) produces superior analyte signal abundance to methane. Isobutane has never been widely adopted for CI-MS because it fouls the ion source more rapidly and produces positive CI spectra that are more strongly dependent on reagent gas pressure compared with methane. Isobutane was diluted to various concentrations in argon for use as a reagent gas with an unmodified commercial gas chromatograph-mass spectrometer. Analyte spectra were directly compared using methane, isobutane, and isobutane/argon mixtures. A mixture of 10% i-C 4 H 10 in argon produced twice the positive-mode analyte signal of methane, equal to pure isobutane, and reduced spectral dependence on reagent gas pressure. Electron capture negative chemical ionization using 1% i-C 4 H 10 in argon tripled analyte signal compared with methane and was reproducible, unlike pure isobutane. The operative lifetime of the ion source using isobutane/ argon mixtures was extended exponentially compared with pure isobutane, producing stable and reproducible CI signal throughout. By diluting the reagent gas in an inert buffer gas, isobutane CI-MS experiments were made as practical to use as methane CI-MS experiments but with superior analytical performance.

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“…7-1.0 Torr. The technique for the mix-h i b i t e d .ing of reagent gases for chemical ionization experiments has been described 15. …”

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confidence: 99%

Mass spectrometry. Comparison of the electron impact and chemical ionization fragmentations of 8,9-dehydro-2-adamantanol and 2-exo-protoadamantenol

Jelus¹,

Munson²,

Babiak³

et al. 1974

J. Org. Chem.

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10%), 229 (7%); nmr 1.12 (s, 3 H, C-4 CH3), no resonance for the C-3 proton. The compound showed a single component on analysis by tic and glc (on four systems noted above).The less polar major component (19.0 mg) on tic showed a mass spectrum which was very similar to that of [3a,4d-2H2]-4a-methylcholest-5-en-3d-ol (V) with additional ions at 399 (90%) and 366 (3%). The nmr spectrum showed the presence of signals 4.95 (m), 5.62 (m), and 8.43 in addition to the resonances seen in the spectrum of III. The spectrum showed no absorbance at 3.71 (C-3 H) or at 3.90 seen in the spectrum of the less polar component obtained as a by-product in the synthesis of IV.

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Reagent gases for G.C.-M.S. analyses

Cited by 52 publications

References 21 publications

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Mass Spectrometric Fragmentation of Trimethylsilyl and Related Alkylsilyl Derivatives

Isobutane Made Practical as a Reagent Gas for Chemical Ionization Mass Spectrometry

Mass spectrometry. Comparison of the electron impact and chemical ionization fragmentations of 8,9-dehydro-2-adamantanol and 2-exo-protoadamantenol

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