Analysed Ion Kinetic Energy Spectra Research Articles

Investigation on Mass Spectral Fragmentation Mechanism of C2‐Symmetric Chiral Bis(oxazoline) and Bis(thiazoline)

AbstractThe electron impact mass spectra of ten new C2‐symmetric chiral bis(oxazoline) and bis(thiazoline) have been studied. Bis(thiazoline) and bis(oxazoline) possess the same fragmentation mechanism under EI conditions. An unusual fragmentation pathway has been found in the compounds studied. Due to the presence of phenyl group, compounds 6 and 10 undergo a new fragmentation pathway except for the common way as the other eight compounds. Mass analyzed ion kinetic energy spectra experiments and high resolution accurate mass measurement were conducted to confirm the proposed fragmentation pathways.

Energetics, kinetics and dynamics of decaying metastable ions studied with a high-resolution three-sector field mass spectrometer

Mass spectrometric analysis of metastable decay reactions is devoted to the measurements of the kinetic energy release distribution (KERD) for the decay of singly charged rare gas dimer ions and , the doubly charged acetylene parent ion and the singly and doubly charged SF6 fragment ions, like for example , and . The KERDs are obtained either from high-resolution mass analysed ion kinetic energy spectra or the measurement of ion beam profiles using a specially improved mass spectrometric system. Due to the high energy resolution measurements and theoretical studies based on ab initio calculations of potential energy curves it is possible to assign the reaction products of the rare gas dimer decays to electronic transitions in the excited parent ion. The and also the ions are investigated because of obscurities in the production of their fragment ions. The unusual shape of the ionization cross section indicates that at sufficiently high electron energies the fragmentation channel of doubly charged contributes significantly to the ion yield. Additional measurements of the corresponding appearance energies confirm the existence of this second production channel.

A tandem mass spectrometry study of trifluoroacetic acid using chemical ionization with methanol and water

Mass analyzed ion kinetic energy spectra (MIKES) were scanned for the following ion species generated with water or methanol as reagent gases under chemical ionization conditions: [CF3CO2CH3H]+, [CF3CO2HH]+, [CF2CO2CH3]+, [CF3CO]+, [CF2CO2H]+, [CF3OH2]+ and [CF3OH]+·. Unimolecular decompositions of the [CF3CO2CH3H]+, [CF3CO2H2]+ and [CF3COH2]+ ions were all associated with a dominant loss of an HF molecule. In labeling experiments, an isotopic kinetic effect was evident for the unimolecular loss of HF from the [CF3CO2HD]+ species, in that the intensity of the peak produced by the HF loss exceeded that pertaining to DF loss by a factor of 10. Further unimolecular transitions were found for protonated trifluoroacetic acid at 87 → 67 and 86 → 67. In the MIKE spectrum of [CF2CO2CH3]+ ions derived from protonated trifluoroacetic acid methyl ester, a dish-shaped peak corresponding to 15 kcal/mol kinetic energy release was found for the loss of CO. On introduction of collision gas, additional characteristic product ions were identified, and their compositions were established using deuterium labeled isotopic variants of the parent ions. © 1998 John Wiley & Sons, Ltd.

Fast atom bombardment of some asymmetric compartmental [1 +1] Schiff bases

New compartmental ligands (L), containing a N2O2 or N3O2 Schiff base and an O2O4, O2O5 or O2O6 ‘crown like’ coordination site, have been prepared by reaction of the appropriate diformyl- and polyamine precursors. The related amine derivatives have been obtained by reduction of the imine analogues with NaBH4. The mass spectrometric behaviour of these compounds has been studied by fast atom bombardment mass spectrometry, which mainly leads to the facile production of protonated [MH]+ and cationized [MNa]+ molecules. The mass analysed ion kinetic energy spectra of these ionic species show that the primary fragmentation patterns strongly depend on the crown dimensions and on the imine–amine structure of the nitrogen-containing chain. Macrocyclic rare earth complexes Me(L)(H2O)4(Cl)3 (Me = Ce, Y), prepared by a template procedure, have been also studied under the same experimental conditions, proving that the presence of the metal ion leads to a strong reduction of the number of primary decomposition pathways. © 1997 John Wiley & Sons, Ltd.

Synthesis and Mass Spectrometric Behaviour of Some New Nucleosides as Potential Anti-HIV Agents

The electron-impact (EI) mass spectrometric behaviour of a series of 8-aza-purines derivatized with hydroxymethylcyclopentane and exhibiting cis-trans isomerization in the cyclopentane ring has been studied in detail with the aid of metastable-ion data. Specific fragmentation processes, present in both EI and mass analysed ion kinetic energy spectra of molecular species, allow characterization of the different pairs of stereoisomers. Contrary to what is observed in the case of purine analogs, the presence of a nitrogen atom in position 8 strongly inhibits fragmentation processes related to the heterocycle. © 1997 John Wiley & Sons, Ltd.

Synthesis and mass spectrometric behavior of some new nucleosides as potential anti-HIV agents.

The electron-impact (EI) mass spectrometric behaviour of a series of 8-aza-purines derivatized with hydroxymethylcyclopentane and exhibiting cis-trans isomerization in the cyclopentane ring has been studied in detail with the aid of metastable-ion data. Specific fragmentation processes, present in both EI and mass analysed ion kinetic energy spectra of molecular species, allow characterization of the different pairs of stereoisomers. Contrary to what is observed in the case of purine analogs, the presence of a nitrogen atom in position 8 strongly inhibits fragmentation processes related to the heterocycle.

Election Impact Mass Spectra of para-Substituted N-Heteroaryl Benzylamines

The 70 eV electron impact mass spectra of some para-substituted N-heteroaryl benzylamines, synthesized through the corresponding Schiff bases, are reported. Typical fragmentation patterns are discussed with the aid of mass analyzed ion kinetic energy spectra and exact mass measurements. The compounds are relatively stable under electron impact, the molecular ion being the base peak or the second most intense ion in the spectra. The dominating breakdown process is the benzylic cleavage, that gives rise to the base peak in some of the investigated compounds and to the second intense peak in others

A novel hydrogen rearrangement of bifunctionalo-xylylene derivatives in chemical ionization mass spectrometry

A novel hydrogen rearrangement reaction was found in benzyl ions that have a (benzyl) group (Z=O or N) at their ortho position. From deuterium labeling experiments, mass analyzed ion kinetic energy spectra with collisional activation, and examination of structure-peak intensity correlation, a mechanism is proposed which involves a direct transfer of hydrogen (hydride) to the structurally remote but spatially close cationic center. The possibility of an alternative, less likely mechanism including an ion/neutral complex and/or a proton-bridged complex has also been discussed.

The Electron Impact Induced Fragmentation of 1-Aryl-5-hydroxy-1,2,3-triazole-4-carboxamides

The pathways of the electron impact induced fragmentation of 1-aryl-5- hydroxy-1,2,3-triazole-4-carboxamides were studied. The compositions of the key ions were confirmed by high-resolution mass spectrometry. The proposed pathways were established from mass analysed ion kinetic energy spectra, and B/E and B2/E linked scans. A variety of structures for the molecular ion of the title compounds is proposed.

Identification of some abnormal haemoglobins by fast atom bombardment mass spectrometry and fast atom bombardment tandem mass spectrometry.

The characterization of two abnormal human haemoglobins by fast atom bombardment (FAB) mapping is presented. The first variant, called 'R', exhibits a tryptic FAB map identical to that of normal haemoglobin. However, using Staphylococcus protease V8, a peptide containing the carboxyl end of the beta-chain exhibits a mass shift down to 300 mass units. This clearly indicates the deletion of the two last amino acids of the beta-chain. The second variant, called 'Grenoble', is due to two different modifications of the beta-chain. The location of the Pro----Ser exchange on peptide T5 is achieved by the collisionally activated dissociation mass analyzed ion kinetic energy spectra of the corresponding [MH]+ ion. The m/z value of that peptide indicated a supplementary acid----amide modification, which was located by amino acid sequencing using chemical methods. This work concludes with the necessity of using complementary methods for achieving rapid determinations of abnormal proteins with minute amounts.

Tandem mass spectrometry in vitamin E analysis.

Tandem mass spectrometry is applied to the tocopherols and representative tocotrienols of the vitamin E family. The collision-induced dissociation/mass analysed ion kinetic energy spectra generated from three ions in the electron impact ionization spectra of 5,7,8-trimethyltocol, 5,7,8-trimethyltocotrienol, 5,7-, 5,8- and 7,8-dimethyltocol and 7,8-dimethyltocotrienol are described. The technique allowed direct physical characterization of each class of tocochromanol, and in the case of monomethyltocols differentiation of 5-methyltocol from the 7- and 8-methyltocol isomers, and its value in analysis of biological tissue extracts is established.

An example of intense artifact peaks in mass analyzed ion kinetic energy spectra and their elucidation using an instrument of BEqQ configuration

Rapid Communications in Mass SpectrometryVolume 2, Issue 5 p. 79-83 Article An example of intense artifact peaks in mass analyzed ion kinetic energy spectra and their elucidation using an instrument of BEqQ configuration† A. J. Alexander, A. J. Alexander Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this authorP. Thibault, P. Thibault Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada Seconded from Biotechnology Research Institute, National Research Council, Montreal, Canada.Search for more papers by this authorR. Guevremont, R. Guevremont Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this authorR. K. Boyd, Corresponding Author R. K. Boyd Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaAtlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this author A. J. Alexander, A. J. Alexander Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this authorP. Thibault, P. Thibault Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, Canada Seconded from Biotechnology Research Institute, National Research Council, Montreal, Canada.Search for more papers by this authorR. Guevremont, R. Guevremont Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this authorR. K. Boyd, Corresponding Author R. K. Boyd Atlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaAtlantic Research Laboratory, National Research Council, 1411 Oxford Street, Halifax, Nova Scotia B3H 3Z1, CanadaSearch for more papers by this author First published: May 1988 https://doi.org/10.1002/rcm.1290020502Citations: 8 † NRCC No. 28727. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume2, Issue5May 1988Pages 79-83 RelatedInformation

A study of multiply charged ions derived from polycyclic aromatic hydrocarbons

Mass analyzed ion kinetic energy spectra (MIKES) have been observed for trications derived from triptycene, triphenylene, perylene, chrysene, and 2,3-benzanthracene. Specifically, the ion kinetic energy releases upon unimolecular charge separation of trications derived from the above compounds have been measured. In addition, mass spectra derived solely from doubly charged and solely from triply charged ions, commonly known as 2 E and 3 E/2 mass spectra, respectively, have been recorded for the above compounds and for benzo[ a]pyrene. From these spectra, attempts have been made to determine the mechanisms by which these trications undergo charge separation. Low-order molecular orbital calculations have been performed for triphenylene and triptycene in order to derive the localized π charge density and the resultant coulombic repulsion within the molecular ion framework. The results of the theoretical calculations agree well with experimental observations and the predicted electronic energy levels offer insight into the origins of the relatively long lifetimes of the tricationic species observed.

The mass spectrometric behaviour of some iridium(I) and iridium(III) pyrazolate derivatives

The mass spectrometric behaviour of a series of monomeric iridium(I) and iridium(III) pyrazolates, Ir(PPh 3) 2(CO)(pz- N) ( 1– 3) and Ir(PPh 3) 2(CO)(H) 2(pz- N) ( 4– 6) ( 1 and 4: pzH = 3,5-dimethylpyrazole; 2 and 5: pzH = 3,5-bis(trifluoromethyl)pyrazote; 3 and 6: pzH = 3,5-dimethyl-4-nitropyrazole), has been studied in detail with the aid of linked scans and mass analysed ion kinetic energy spectra. The differences observed as a function of the substituents on the pyrazolate ligands are described, and a comparison with the results previously reported for homologous rhodium(I) derivatives is made. The reactions leading, under the experimental conditions, to binuclear species or to orthometallated derivatives are discussed.

Collisional spectroscopy for unequivocal and rapid determination of morphine at ppb level in the hair of heroin addicts.

A new analytical procedure for the identification of morphine in the hair of heroin addicts has been developed using collisional spectroscopy, on a commercially available, reverse geometry, double focusing instrument. Either collision-induced dissociation (B/E = const) linked scans or mass analysed ion kinetic energy spectra lead to an unequivocal and rapid determination of morphine in hydrolysed hair extract which may be compared with the data obtained by different and more traditional analytical methods.

Ion chemistry of phthalamic acids. III. The origin of [M  1]+ ions under electron impact

AbstractElectron impact mass spectra and collisional activation/mass‐analysed ion kinetic energy spectra of some phthalamic acids and their deuterium labelled analogues suggested that the genesis of [M  1]+ ions is due to the loss of an aromatic hydrogen ortho to the amidic group, as for aromatic amides and thioamides.

Fragmentation process of benzenedicarboxylic acid dimethyl esters.

Fragmentation process of 1,2-([1]), 1,3-([2]) and 1,4-([3]) benzenedicarboxylic acid dimethyl esters by electron impact has been investigated by using deuterium labelling techniques, ion kinetic energy and mass analyzed ion kinetic energy spectra. The fragmentation process of [1] is somewhat distinct from those of [2] and [3], due to the interaction of each substituent (that is, an ortho effect).By taking thermochemical data into account, it is demonstrated that the structure of the intermediate ion, [C8H5O2]+ (m/z 133), generated from [1], is the same as that of the ion at m/z 133 due to loss of a hydrogen atom from the molecular ion of 1,2-benzenedicarbaldehyde, ([4]).

The behaviour of stereoisomeric ions in the gas‐phase. The case of some new macrocyclic ether‐tetraesters

AbstractThe electron impact mass spectrometric behaviour of some new diastereoisomeric macrocycles containing diglycolyl moiety as subcyclic unit is reported and discussed in detail with the aid of linked scans, exact mass measurements and collisionally activated decomposition mass analyzed ion kinetic energy spectra.

Electron impact mass spectrometry of some 2,3‐dihydro‐1‐benzofuran‐3‐acetic acids

AbstractThe mass spectrometric behaviour of four 2,3‐dihydro‐1‐benzofuran‐3‐acetic acids has been studied in detail with the aid of exact mass measurements, linked scans, collisionally activated decomposition, mass analysed ion kinetic energy spectra and labelling experiments. Unusual fragmentation pathways are emphasized for which mechanisms are proposed.

Electron impact mass spectrometry of some benzodioxole derivatives of pharmacological interest, their synthons and synthetic intermediates

AbstractThe mass spectrometric behaviour of two newly synthesized β‐blocking benzodioxole derivatives, their synthons and synthetic intermediates has been studied in detail with the aid of exact mass measurements, linked scans, collisionally activated decomposition mass analysed ion kinetic energy spectra and deuterium labelling experiments. A retrosynthetic process, leading to the original synthons, is described.