Argon-water mixtures as reagents for chemical ionization mass spectrometry

Hunt, Donald F.; Ryan, James F.

doi:10.1021/ac60315a024

Cited by 62 publications

(21 citation statements)

References 16 publications

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“…For PCI-MS analysis of breath VOCs, other liquid reagent with greater PA such as methanol (PA at 761 KJ mol −1 ) generated distinctive amount of dimers and trimers that may interfere the interpretation of compound identity 33 . Contrary to a previous study 34 showing that PCI of 4-decanone with water reagent also afforded excessive [2 M + H] + of m/z 313, no dimer peak formation was observed in the ketone analysis performed in this work. Water infusion was previously reported in atmospheric pressure chemical ionisation analysis 35 which favoured the detectability and reproducibility of metabolome derivatives.…”

Section: Discussioncontrasting

confidence: 99%

Cross-platform mass spectrometry annotation in breathomics of oesophageal-gastric cancer

Chin

Romano

Doran

et al. 2018

Sci Rep

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Disease breathomics is gaining importance nowadays due to its usefulness as non-invasive early cancer detection. Mass spectrometry (MS) technique is often used for analysis of volatile organic compounds (VOCs) associated with cancer in the exhaled breath but a long-standing challenge is the uncertainty in mass peak annotation for potential volatile biomarkers. This work describes a cross-platform MS strategy employing selected-ion flow tube mass spectrometry (SIFT-MS), high resolution gas chromatography-mass spectrometry (GC-MS) retrofitted with electron ionisation (EI) and GC-MS retrofitted with positive chemical ionisation (PCI) as orthogonal analytical approaches in order to provide facile identification of the oxygenated VOCs from breath of cancer patients. In addition, water infusion was applied as novel efficient PCI reagent in breathomics analysis, depicting unique diagnostic ions M+ or [M-17]+ for VOC identification. Identity confirmation of breath VOCs was deduced using the proposed multi-platform workflow, which reveals variation in breath oxygenated VOC composition of oesophageal-gastric (OG) cancer patients with dominantly ketones, followed by aldehydes, alcohols, acids and phenols in decreasing order of relative abundance. Accurate VOC identification provided by cross-platform approach would be valuable for the refinement of diagnostic VOC models and the understanding of molecular drivers of VOC production.

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Section: Discussioncontrasting

confidence: 99%

Cross-platform mass spectrometry annotation in breathomics of oesophageal-gastric cancer

Chin

Romano

Doran

et al. 2018

Sci Rep

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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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“…10, NO. 10 ions are very weak, and the spectrum is complicated by the presence of a series of non-sequence ions arising from losses of neutral molecules from the [M+ HI' ion. Chemical ionization using a noble reagent gas, which reacts with the sample to transfer an electron from the sample to the reactant ion, produces an odd-electron molecular ion and leads to fragmentation similar to electron ionization.…”

Section: Gas Chromatography Mass Spectrometry (Gc/ms)mentioning

confidence: 99%

Mixed gas chemical ionization mass spectrometry of peptide derivatives

Yates

Anderegg

1983

Biol. Mass Spectrom.

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In chemical ionization mass spectrometry, the use of a noble reagent gas mixed with a proton transfer reagent gas is known to produce mass spectra which contain both protonated molecules and fragment ions. We have used a mixture of isobutane and argon to improve the mass spectra of peptides which have been derivatized to O-TMS-polyamino alcohols. The molecular weight is deduced from a prominent [M+ H]+ ion; the sequence of amino acids is deduced from the usual A-and Z-series fragment ions. This technique enhances the sequence ions for lysine and glycine-containing peptides, and retains the ability to distinguish C-terminal leucine and isoleucine.

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Argon-water mixtures as reagents for chemical ionization mass spectrometry

Abstract: chamber which has a greater heat capacity and a better temperature controller would probably increase the sensitivity considerably.

Cited by 62 publications

References 16 publications

Cross-platform mass spectrometry annotation in breathomics of oesophageal-gastric cancer

Cross-platform mass spectrometry annotation in breathomics of oesophageal-gastric cancer

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

Mixed gas chemical ionization mass spectrometry of peptide derivatives

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