In‐beam ionization by alkali ion attachment applying a two‐filament ion source

Schmelzeisen‐Redeker, G.; Giessmann, U.; Röllgen, F. W.

doi:10.1002/oms.1210200408

Cited by 20 publications

(9 citation statements)

References 17 publications

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“…Ions, such as Na + , leave the sur face and combine in the gas phase with desorbed neu tral molecules via ion-dipole interactions [9,14], Several interesting studies have also been done on IR and thermal desorption of neutrals using postionization techniques. Allison et al [15] and Röllgen et al [16] showed that the emitted neutrals could be ionized in the gas phase by using an intersecting Reprint requests to Dr. J. Grotemeyer, Institut für Physi kalische und Theoretische Chemie, Technische Universität München, Lichtenbergstraße 4, D-8046 Garching, BRD.…”

Section: Introductionmentioning

confidence: 99%

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Beavis

Lindner

Grotemeyer

et al. 1988

Zeitschrift Für Naturforschung A

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I n f r a r e d D e s o r p tio n o f N e u t r a l M o le c u le s E m b e d d e d in T r a n s p a r e n t M a tr ic e s R.C. Beavis, J. Lindner, J. Grotemeyer, and E.W. Schlag Institut für Physikalische und Theoretische Chemie, Technische Universität München Z. Naturforsch. 43a, 1083Naturforsch. 43a, -1090Naturforsch. 43a, (1988; received July 25, 1988 The desorption of intact molecules by pulsed IR irradiation is shown to depend on the IR absorption of the matrix. IR transparent matrices, such as NaCl or NH4N03, increase the total yield and the shot-to-shot stability of the sample. IR absorbing matrices decrease the yield of intact molecules and increase the amount of pyrolysis products.Using semi-transparent sugar matrices with dipeptide samples, the most intense fragment, i.e. the parent molecule having lost 18 u, is suppressed. This fragment is formed by pyrolysis during IR desorption. Three other prominent fragments are caused by the UV photoionization step.The experimental results suggest that a model involving bulk stresses and strain may be necessary to explain the observations.

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Section: Introductionmentioning

confidence: 99%

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Beavis

Lindner

Grotemeyer

et al. 1988

Zeitschrift Für Naturforschung A

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“…There are a number of advantages in using potassium ions here although we do not suggest that it is the optimum cation that can be used for such work (17). Allison and Ridge (25) have shown the ability of an alkali ion to induce fragmentation following complexation decreases when going down the column in the periodic table.…”

Section: Resultsmentioning

confidence: 94%

“…Recently they have reported a technique using a two-filament design (17). In a specially constructed ion source, two filaments are in close proximity, mounted on a common "push rod".…”

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confidence: 99%

Desorption/ionization mass spectrometric technique for the analysis of thermally labile compounds based on thermionic emission materials

Bombick¹,

Allison²

1987

Anal. Chem.

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When a thermally labile analyte Is placed on a potassium thermionic emitter and heated, Ions representative of the sample are formed. This has been developed Into a new Ionization technique which utilizes a thermionic emitter probe that can be used with any mass spectrometer having a direct Insertion probe. A possible mechanism for this Ionization method is discussed. The proposed mechanism Involves the gas-phase addition of emitted potassium Ions to neutrals desorbed from the surface. This Ionization method Is referred to as K+IDS (K+ Ionization of desorbed species). Examples of K+IDS spectra are given for a variety of compounds Including saccharides, pharmaceuticals, peptides, steroids, and polymers. The analysis of mixtures Is also demonstrated here.In addition to the K+ Ionization of desorbed species, surface Ionization can occur. Surface Ionization Is demonstrated for the class of compounds that Includes xanthine and theophylline. Surface Ionization can also occur for thermally labile compounds, producing negative Ions; this Is shown here by use of a peptide as an example.

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“…All mass spectrometric analysis were performed on an unmodified HP5985 GC/MS/DS quadrupole mass spectrometer (Hewlett-Packard, Avondale, PA) with a mass range of 10-1000 Da equipped with a modified direct insertion probe, similar to that reported previously by Rollgen and co-workers [11] and by Kassel and Allison et a1. [12].…”

Section: Methodsmentioning

confidence: 99%

Characterization of the primary thermal degradation processes of peptides using the mass spectrometric technique K⁺IDS, K⁺ ionization of desorbed species

Allison

1994

J. Am. Soc. Mass Spectrom.

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The mass spectrometric technique of K(+) ionization of desorbed species, K(+)IDS, is used here to characterize the primary thermal degradation chemistry of small peptides. In this technique, a small amount of a compound is rapidly heated in the condensed phase. Desorption of the intact molecule can occur. Also, thermal degradation products are formed which quickly desorb as well, rather than remain on the surface and undergo subsequent chemistry. The desorbed molecules form adducts with gas phase K(+) ions, and a mass spectrum is obtained. Deuterium labeling experiments, and the use of derivatizing reagents, allows for the thermal degradation chemistry of small peptides to be elucidated. Apparently, skeletal bond cleavages are accompanied by H-shifts, although the hydrogen atoms shift from "remote" sites, brought into close proximity with the fragmenting skeletal bond via secondary interactions. Experimental results are presented that allow for correlations between thermal degradation chemistry and the resulting K(+)IDS mass spectra to be made.

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In‐beam ionization by alkali ion attachment applying a two‐filament ion source

Cited by 20 publications

References 17 publications

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Desorption/ionization mass spectrometric technique for the analysis of thermally labile compounds based on thermionic emission materials

Characterization of the primary thermal degradation processes of peptides using the mass spectrometric technique K⁺IDS, K⁺ ionization of desorbed species

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In‐beam ionization by alkali ion attachment applying a two‐filament ion source

Cited by 20 publications

References 17 publications

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Infrared Desorption of Neutral Molecules Embedded in Transparent Matrices

Desorption/ionization mass spectrometric technique for the analysis of thermally labile compounds based on thermionic emission materials

Characterization of the primary thermal degradation processes of peptides using the mass spectrometric technique K+IDS, K+ ionization of desorbed species

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Product

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Characterization of the primary thermal degradation processes of peptides using the mass spectrometric technique K⁺IDS, K⁺ ionization of desorbed species