Origins and structures of background ions produced by fast-atom bombardment of glycerol

Caldwell, Kenneth A.; Gross, Michael L.

doi:10.1016/1044-0305(94)85039-9

Cited by 16 publications

(6 citation statements)

References 60 publications

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“…The observation that beam-induced dehalogenation decreases with increasing analyte electron affinity is evidence that mechanistically is consistent with the proposition that secondary electron production is an intrinsic part of the bombardment process. Our results constitute evidence for the proposition made by others [34,40,[45][46][47][48] with regard to the initial processes that occur upon kiloelectronvolt particle impact where glycerol molecules are ionized through ejection of secondary electrons. The a-hydroxyalkyl radicals that stem from the bombardment of glycerol are proposed to be potential contributors to beam-induced reduction processes because such radicals engage in one electron reductions.…”

Section: Conclusion Acknowledgmentssupporting

confidence: 89%

“…The reducing species (in order of "reducing power") are the electrons, hydrogen atoms, and o-hydroxyalkyl radicals; the latter are carbon-centered radicals. The generation of such C-centered radicals upon kiloelectronvolt particle bombardment of glycerol has been established firmly [19,[32][33][34]. These o-hydroxyalkyl radicals can be effective electron transfer agents [35].…”

Section: Electron Affinity (Ev)mentioning

confidence: 99%

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Evidence for a mechanism that involves secondary electron capture in the liquid secondary ionization mass spectrometry beam-induced dehalogenation of organic compounds

Théberge

Bertrand

1996

J. Am. Soc. Mass Spectrom.

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The effect of the analyte electron affinity on the liquid secondary ionization mass spectrometry beam-induced dehalogenation of simple bromoaromatic compounds in a glycerol matrix was investigated. The results show a definite trend of decreasing dehalogenation with increasing analyte electron affinity. At high analyte electron affinity (≥ 1.0 eV), no dehalogenation was observed. These results are consistent with electrochemical and pulse radiolysis studies where one electron reduction was shown to be responsible for dehalogenation. A chloroaromatic compound with high electron affinity, 4-(4-chloro-benzoyl)pyridine, exhibited reduction by hydrogen addition but not dehalogenation. The radiation chemistry of alcohols was used to elaborate a scheme of the reactive species generated in the glycerol matrix by kiloelectronvolt particle bombardment. The possible role of those species in reduction processes such as dehalogenation was evaluated. The observation that dehalogenation decreases with analyte electron affinity is mechanistically consistent with the proposition that secondary electron production is an intrinsic part of the bombardment process.

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Section: Conclusion Acknowledgmentssupporting

confidence: 89%

Section: Electron Affinity (Ev)mentioning

confidence: 99%

Evidence for a mechanism that involves secondary electron capture in the liquid secondary ionization mass spectrometry beam-induced dehalogenation of organic compounds

Théberge

Bertrand

1996

J. Am. Soc. Mass Spectrom.

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“…Furthermore, the spectrum of atrazine in HEDS reveals the presence of analyte matrix adduct which can be reasonably explained in terms of radical-radical recombination involving HOCH,CH,S'. 51 Sulfur compounds are known to be involved in the protection mechanism for biological systems subjected to ionizing radiation or other forms of free radical damage." That sulfur plays a role in inhibiting the dehalogenation process appears undeniable since MES, which has three sulfurs and no other heteroatom, exhibited the lowest non-zero dehalogenation value of all the matrices used for atrazine.…”

Section: Effect Of Liquid Matrixmentioning

confidence: 99%

Beam‐induced dehalogenation in LSIMS: Effect of halogen type and matrix chemistry

Théberge

Bertrand

1995

J. Mass Spectrom.

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The LSIMS beam-induced dehalogenation of several 4-halo-phenylalanine methyl esters (I, Br, CI, F) was investigated and compared to that of atrazine using 12 different matrix compounds including diethyl phthalate for which the empirical electron affinity was known. The extent of dehalogenation, induced by a one-electron reduction process, is in agreement with the leaving group ability of the corresponding halogens~(1 > Br > CI > F) and the dehalogenation inhibiting efficiency of the matrices. The latter is rationalized in terms of electron scavenging capacity and matrix structural features relating to that capacity. The extent of dehalogenation observed for 4-1-phenylalanine methyl ester is similar to that of atrazine, a chlorinated compound, which indicates that the halogen effect is not overwhelming in determining the extent of dehalogenation. The bracketing of matrix reduction potential was attempted based on the propensity of the matrices to induce M+' formation from analytes of known oxidation potentials. The ability of matrices to induce M" formation parallels their dehalogenation and reduction inhibiting efficiencies. The last observation underlines the importance of matrix redox properties in effecting or inhibiting beam-induced processes, be they reductive or oxidative.

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“…[72][73][74][75][76] Voluminous mass spectrometric information on glycerol at both ambient and LT conditions is available. 21,24,26,33,60,91 A water-glycerol mixture gives a typical example of LT-FAB mass spectra of a two-component system whose phase diagram is of the same type as presented in Figure 4. In accord with the model for interpretation of the LT-FAB mass spectra, described in the previous section, it is necessary to determine the morphology of the samples formed during freezing (much studied for water-glycerol mixture by cryobiology [72][73][74] ).…”

Section: Water-cryoprotector Mixturesmentioning

confidence: 99%

Low temperature secondary emission mass spectrometry. Cryobiological applications

Kosevich

1998

Eur. J. Mass Spectrom.

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Recent achievements of low temperature secondary emission mass spectrometry in exotic fields of life sciences such as cryobiology are surveyed. Specific problems of molecular cryobiology and cryobiophysics accessible to mass spectrometric investigation are defined and the potential of low temperature fast-atom bombardment and secondary ion mass spectrometry in studies of frozen water and cryoprotector solutions of biologically active compounds are demonstrated. Emphasis is placed on the elucidation of changes in intermolecular interactions, the binding of metal ions, water and cryoprotectors with biomolecules at reduced temperatures in comparison with ambient conditions. A model for interpretation of the low temperature secondary emission mass spectra, based on details of phase diagrams of the system under study, the heterogeneous structure of the sample resulting from phase separation during freezing and phase transitions in the sample with temperature variation is discussed.

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Origins and structures of background ions produced by fast-atom bombardment of glycerol

Cited by 16 publications

References 60 publications

Evidence for a mechanism that involves secondary electron capture in the liquid secondary ionization mass spectrometry beam-induced dehalogenation of organic compounds

Evidence for a mechanism that involves secondary electron capture in the liquid secondary ionization mass spectrometry beam-induced dehalogenation of organic compounds

Beam‐induced dehalogenation in LSIMS: Effect of halogen type and matrix chemistry

Low temperature secondary emission mass spectrometry. Cryobiological applications

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