Pulsed positive negative ion chemical ionization mass spectrometry

Hunt, Donald F.; Stafford, George C.; Crow, Frank W.; Russell, John Wellesley

doi:10.1021/ac50008a014

Cited by 293 publications

(117 citation statements)

References 18 publications

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“…Methane was the first reagent gas used for CI and remains by far the most common, almost to the total exclusion of other gases in contemporary experiments. The principal positive reagent ions from methane, CH 5 + and C 2 H 5 + , react with almost all organic molecules, and methane CI spectra are largely independent of reagent gas pressure in the ion source [2,3]. When resonance electron capture (EC) ionization was adapted for negative chemical ionization (NCI) mass spectrometry, methane was used as reagent gas to thermalize electrons [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…The principal positive reagent ions from methane, CH 5 + and C 2 H 5 + , react with almost all organic molecules, and methane CI spectra are largely independent of reagent gas pressure in the ion source [2,3]. When resonance electron capture (EC) ionization was adapted for negative chemical ionization (NCI) mass spectrometry, methane was used as reagent gas to thermalize electrons [4][5][6]. Although more efficient gases for EC-NCI-MS have long been identified [7], methane continues to be the most popular choice [8,9].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

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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“…8). In general, negative ion mass spectrometry has hitherto not been popular in the area of structure elucidation, because of poor sensitivity.…”

Section: Hg)mentioning

confidence: 99%

Structural and Sequencing Studies on Peptides, Proteins, and Glycopeptide Antibiotics by Mass Spectrometry

Williams¹

1978

Mass Spectrometry of Natural Products

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-Mass spectrometry is now established as a useful method for establishing the sequence of small peptides (2-10 residues), following their derivatisation (by N-acetylation and permethylation) to increase volatility.The strength of the method lies in its ability to deal with simple mixtures of peptides and to identify unusual amino acids.The weakness of the method (relative to some wet-chemical approaches to sequencing) lies in the current inability of the method to sequence larger peptides, and the relatively low sensitivity when working with peptides near the molecular weight limit of the method.This last shortcoming is due to our present inability to volatilise and efficiently produce high mass ions from the larger peptides, the inherent sensitivity of mass spectrometry being in contrast extremely high.The use of deuterated reagents in degradation and derivatisation reactions provides a powerful method for structure elucidation of glycopeptide antibiotics containing unusual amino acids.

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“…It has been suggested that mass spectrometric determination in negative ion mode can be two orders of magnitude more sensitive than positive ion methodologies [15]. Accordingly, in this report, we develop a method for quantification of long-chain aldehydes utilizing PFB oxime formation and GC-MS analysis in the NICI mode.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Pentafluorobenzyl Oxime Derivatives of Long Chain Aldehydes by GC–MS Analysis

Brahmbhatt

Nold

Albert

et al. 2008

Lipids

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Negative ion mass spectrometric techniques for compounds having good ionization properties, such as pentafluorobenzyl derivatives, are believed to be more sensitive than positive ion methods. In this study we develop a technique of quantification of long-chain aldehydes by analysis of their pentafluorobenzyl oxime derivatives utilizing gas chromatography-mass spectrometry in the negative ion chemical ionization mode. We establish that separation of plasmalogens prior to pentafluorobenzyl derivatization is essential and achieve this separation over a silica column. We further demonstrate the sensitivity of this method and utilize this technique to identify increases in hexadecanal and octadecanal in 3-aminotriazole treated human neutrophils.

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Pulsed positive negative ion chemical ionization mass spectrometry

Cited by 293 publications

References 18 publications

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

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

Structural and Sequencing Studies on Peptides, Proteins, and Glycopeptide Antibiotics by Mass Spectrometry

Quantification of Pentafluorobenzyl Oxime Derivatives of Long Chain Aldehydes by GC–MS Analysis

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