Scanning of sector mass spectrometers to observe the fragmentations of metastable ions

Boyd, Robert K.; Beynon, J. H.

doi:10.1002/oms.1210120311

Cited by 219 publications

(44 citation statements)

References 10 publications

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“…This was true (15,16) in cases where several other possibilities existed for the origins of the first CO fragment. By analogy with the case of 2-pyrone, it has been widely surmised (3) that the C 8 H 6 0 + ' ion, formed by loss of CO from the molecular ion of 4, has the closed-ring structure of benzofuran (5). This suggestion has been challenged on energetic grounds (17); it was suggested (17) that the C 8 H 6 0 + ' ion from 4 has a structure corresponding to that of o-ethynylphenol (7).…”

Section: Fig 1 Collisonally Activated Spectra Of Molecular Ions Of mentioning

confidence: 99%

Mass spectrometry of some furanocoumarins

Tang¹,

McGowan²,

Singh³

et al. 1979

Can. J. Chem.

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Can. J. Chem. 57, 1995 (1979). The mass spectra of two isomeric methoxyfuranocoumarins have been investigated using electron-impact ionisation. Unambiguous distinction between the two isomers is possible through a combination of conventional mass spectra with collision-induced dissociations of the molecular ions and of selected fragment ions. The fragmentation mechanisms of these and related molecular systems were investigated in an attempt to identify the fate of each oxygen atom under electron-impact conditions. To this end, 2-pyrone, benzpyrone (coumarin), benzofuran, and some of its structural isomers were synthesised and studied via metastable spectra, collisionally activated spectra, appearance potentials, and kinetic energy release. Only partial success was achieved in this investigation, but it was possible to write a mechanistic scheme consistent with the present findings and literature data. If valid, this scheme permits identification of two of the four oxygen atoms in the methoxyfuranocoumarins.

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Section: Fig 1 Collisonally Activated Spectra Of Molecular Ions Of mentioning

confidence: 99%

Mass spectrometry of some furanocoumarins

Tang¹,

McGowan²,

Singh³

et al. 1979

Can. J. Chem.

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“…The fragment ion intensities are those obtained for metastable molecular ions which fragmented in the first field-free region of a conventional double-focussing mass spectrometer. They were obtained as peak heights observed in linked scans at constant BIE, and thus correspond to the heights of t h e full metastable 'Revision received June 18, 1982. peaks (6).…”

Section: Polycyclic Aromatic Hydrocarbons ( a ) Experimental Resultsmentioning

confidence: 99%

“…[4]- [6], the various F+ and M+ are ion fluxes of product (fragment) ions and molecular (parent) ions, respectively. M+,, is the total flux of molecular ions produced, while M+ob, is the flux which survives to the detector, and is measured a s the molecular ion intensity in the conventional Can.…”

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confidence: 99%

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Correlations between spectroscopic properties of aromatic molecules and fragmentation rates of their metastable molecular ions in a mass spectrometer

Boyd¹,

Shushan²

1982

Can. J. Chem.

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. Can. J. Chem. 60,2484Chem. 60, (1982. Unexpected correlations have been found between spectroscopic (uv and nmr) properties of some aromatic systems (specifically polycyclic aromatic hydrocarbons and chlorinated biphenyls) and fragmentation rates of the corresponding metastable molecular ions in a field-free region of a mass spectrometer. The meaning of these empirical correlations is explored via the quasi-equilibrium theory of mass spectra. For the caseof the polycyclic aromatic hydrocarbons forwhich more complete ancillary data areavailable, a reasonably self-consistent account of the correlations can be obtained via the ionisation energy as the crucial parameter. The case of the chlorinated biphenyls is less clear, due to a lack of subsidiary data. However, the best explanation available appears to involve a systematic shift in the energy deposition function with increasing steric interaction around the biphenyl linkage. Chem. 60, 2484Chem. 60, (1982. On a trouve des correlations inattendues entre les proprietes spectroscopiques (uv et rmn) de quelques systemes aromatiques (hydrocarbures aromatiques polycycliques et chlorobiphenyles specifiquement) et les vitesses de fragmentation des ions moleculaires metastables correspondants dans la region de libre champ d'un spectromktre de masse. On explore la signification d e ces correlations empiriques via la thCorie de quasi Cquilibre des spectres de masse. Dans le cas des hydrocarbures aromatiques polycycliques, pour lesquels on dispose de donnees accessoires complktes, on peut obtenir une interpretation raisonnablement valable des correlations par l'intermediaire de I'energie d'ionisation comme paramktre fondamental. Le cas des chlorobiphCnyles est moins clair, a cause du manque de donnees secondaires. Cependant, la meilleure explication disponible semble impliquer un glissement systematique dans la fonction d'energie de precipitation avec une augmentation de I'interaction stCrique autour de la liaison biphenyle.[Traduit par le journal] Introduction In some recent work (I), devoted to exploiting the diagnostic capabilities of metastable ion studies in differentiating between isomeric chlorinated biphenyls (PCBs), a correlation was observed between the fragmentation intensities and the number of chlorine substituents ortho to the biphenyl linkage. This correlation, which had been noticed before (2) in the conventional mass spectra of these compounds, was attributed (2) to relief of steric strain in the molecular ions following expulsion of one or more chlorine atoms. In an attempt to improve upon this correlation, a parameter more sensitive to steric strain was sought. The so-called A-band of bi~henvls (3) in the ultraviolet is attributed (3) to a transition to an excited state involving delocalisation over two quinonoid rings via a double-bond linkage. This view will be discussed more fully below, but clearly bulky ortho substituents will restrict the degree of attainable coplanarity, and thus affect the transition energy. An unexpectedly significant correla...

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“…For all this early work, sector instruments were used exclusively and CID was performed at high kinetic energies. There was a lot of research effort focused on MS/MS sector instrumentation at this time [13][14][15][16][17][18][19][20][21][22]. However, in 1978, Yost and Enke published the first results using CID in a triple quadrupole system for MS/MS [23].…”

Section: Beam-beam Hybrid Instrumentsmentioning

confidence: 99%

Hybrid mass spectrometers for tandem mass spectrometry

Glish

Burinsky

2008

J. Am. Soc. Mass Spectrom.

102

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Mass spectrometers that use different types of analyzers for the first and second stages of mass analysis in tandem mass spectrometry (MS/MS) experiments are often referred to as "hybrid" mass spectrometers. The general goal in the design of a hybrid instrument is to combine different performance characteristics offered by various types of analyzers into one mass spectrometer. These performance characteristics may include mass resolving power, the ion kinetic energy for collision-induced dissociation, and speed of analysis. This paper provides a review of the development of hybrid instruments over the last 30 years for analytical applications. (J Am Soc Mass Spectrom 2008, 19, 161-172) © 2008 American Society for Mass Spectrometry T andem mass spectrometry (MS/MS), in a very generic description, is a process in which an ion formed in an ion source is mass-selected in the first stage of analysis, reacted, and then the charged products from the reaction are analyzed in the second stage of analysis. The type and quality of data that is obtained can vary greatly depending upon the type of analyzer used in the first and second stages of analysis, and the type of reaction performed between the stages of analysis. The reactions that can be done also can depend upon the type of analyzer. Over the years there have been a variety of means developed to measure the mass-to-charge ratio of gas-phase ions. The most common methods involve: dispersion based on ion momentum or kinetic energy (magnetic and electric sector instruments); separation in time based on ion velocity (time-of-flight); transmission through an electrodynamic field (quadrupole mass filter); and periodic motion in a magnetic or electrodynamic field (ion traps). There are differences in the experimental parameters associated with these various analysis methods that are pertinent to the MS/MS experiment. Some parameters are obvious, typically related to the performance of the mass analyzer while others are more subtle, related to the reactions/chemistry occurring between the stages of analysis. Many times these different parameters are used to categorize MS/MS experiments.One parameter is the ion kinetic energy. Sector and time-of-flight (TOF) instruments typically operate at "high" ion kinetic energies (5-20 keV), whereas "low" ion kinetic energies (Ͻ50 eV) are typical in quadrupole mass filters and ion traps. The ion kinetic energy is an important parameter in MS/MS experiments because the most common reaction involves colliding the ion of interest with a target gas atom or molecule. When performing ion-neutral collision experiments, the possible reactions that can be accessed (e.g., collisioninduced dissociation, collisional cooling, charge permutation, ion/molecule reaction) depends upon the ion kinetic energy. The appearance of the MS/MS spectrum can change drastically as a function of the collision (ion kinetic) energy. A related factor that is equally important, but often not considered, is the time frame of the experiment, that is, the elapsed time bet...

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Scanning of sector mass spectrometers to observe the fragmentations of metastable ions

Cited by 219 publications

References 10 publications

Mass spectrometry of some furanocoumarins

Mass spectrometry of some furanocoumarins

Correlations between spectroscopic properties of aromatic molecules and fragmentation rates of their metastable molecular ions in a mass spectrometer

Hybrid mass spectrometers for tandem mass spectrometry

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