Letters to the editor

Fraefel, A.; Seibl, J.; Davies, Noel W.; Bignall, John C.; Lincolne, R.; Gonzalez, Jaime Espinosa; Grützmacher, Hans‐Friedrich; Lifshitz, Chava; Goldenberg, Moshe; Malinovich, Y.; Peres, M.; Holzmann, Gerhard; Frenking, Gernot; Steiner, Bernd; Caldwell, Gary W.; Bartmess, John E.; Eckart, Klaus; Schwarz, Helmut; Kobayashi, Shinjiro; Taniguchi, Hiroshi; Taylor, Lester C. E.

doi:10.1002/oms.1210170910

Cited by 7 publications

(1 citation statement)

References 65 publications

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“…To emphasize the limitation it is desirable that symbols evocative of, but distinct from, 'parent ion mlz' and 'daughter ion m/z' be assigned to (V/ V,)(EdE)'m, and (EdE)m,, respectively. In fact the symbols M, and md/y, 13 and n and S, 14 have been so defined. An analogous result for second FFR metastable peaks from instruments of reversed geometry may be achieved by using as coordinates ( VJV)mB and ( Vo/V)2(E/Eo)mB, which have been as-…”

Section: Coordinate Systems For Double Focusing Mass Spectrometersmentioning

confidence: 99%

Graphical aids and scanning modes for tandem mass spectrometry

Macdonald

Lacey

1984

Org. Mass Spectrom.

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In tandem mass spectrometry, where typically one analyser is used to study the reactions of ions selected by another andyser from a mixture teaving the ion source, the output contains an additional dimension of information compared to that from conventional mass spectrometry. me increase in dimensionality tends to make the results less easy to assimilate and interpret, but the diflticulties may be overcome in large measure by presenting the results in an appropriate graphical form. This review deals with the use of graphical representations of three-drm * ensional data to display the results of experiments in tandem mass spectrometry. Perspective diagrams or contour map can be used to show the identity of the parent and daughter ions for all of the reactions occurring in a tandem mass spectrometer, including reactions of positive ions, reactions of negative ions and charge inversion reactions. A graphical approach is particularly valuable when double focusing mass spectrometers are used for tandem mass spectrometry, because it can make it much easier to establish the ongin of the ions contrhthg to an observed peak and thus to determine whether interference is occurring. Factors bearing on the choice of a coordinate system are dl9cnssed. Relationships characterizing the more important simple and linked scanning modes are listed and the features to which they correspond in two selected coordinate systems are shown. Factors that intluence the resolution of neighbouring peaks by sector field tandem mass spectrometers are discussed.

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Section: Coordinate Systems For Double Focusing Mass Spectrometersmentioning

confidence: 99%

Graphical aids and scanning modes for tandem mass spectrometry

Macdonald

Lacey

1984

Org. Mass Spectrom.

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Selective analysis of metastable ions

Fraefel¹,

Seibl²

1985

Mass Spectrometry Reviews

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Accurate linked scans based on digital real time mass linearization and function generation

Friedli¹

1984

Org. Mass Spectrom.

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A new, commercially available digital linked scan unit mass display/macker is presented operating in real time in a mass range of 0.0 to 1638.3 u without the need for a data system. The prerequkites and limitations of successful linked scans with their consequences for the new design are discussed. Examples give evidence of the need for increased accuracy. INTRODUCI'ION ~~Linked scans and mapping techniques are well-known means of establishing the fragmentation pathway of ions outside the ion source. Parent ion search experiments at a given daughter ion mass m2 and daughter ion search experiments at a given parent ion mass ml have both been successfully used in mixture analysis and structure elucidation.' More recently, constant neutral loss scans have been introduced. They allow the search for ions fragmentating by loss of a given uncharged mass Am.2*3 These scans are especially useful in mixture analysis when looking for ions with identical functional group^.^ Thus, linked scans on double focusing sector type mass spectrometers now offer possibilities of using MS/MS techniques, which are typically performed by the more complex triple stage instruments. Limitations exist however, arising mainly from the parameters varied by the scans, the geometry of the mass spectrometer and the possible occurrence of artefact peaks.The mass number of singly charged ions rn* transmitted in standard in-focus spectra ( E = E,, V = V,) defines a convenient measure for the magnetic field B.If exclusively singly charged ions are assumed, the daughter ions of dissociations outside the ion source will only be transmitted by the magnetic sector at m* = m22/m1. Examples are the well-known metastable peaks arising from dissociations within the field free region (FFR) preceding the magnetic field. They are observed in single focusing and conventional geometry double focusing mass spectroscopy. In general m* is not sufficient to deduce m,, m2 and Am. The observation of better defined diffuse peaks is, however, possible with double focusing instruments, preferably by linked scans varying B and the electric sector voltage E simultaneously, according to suitable scan laws. The acceleration voltage V, thereby remains constant in order to avoid detuning of the ion source and unnecessary limitation of the range of observable m a~s e s .~ Daughter ions m2 arising from dissociations in the first field free region (FFR1) in between the accelerating field (ACCF) and the first sector field and, on instruments of reversed geometry, from dissociations within WR2, the region in between the two sector fields, are thereby detected. These ions are transmitted by the electrostatic analyser (ESA) with reduced E at E/E, = mJm, due to the loss of mass and hence of energy. The two instrument-independent quantities m" and E/E, characterize the location of diffuse peaks and allow the determination of m,, m2 and Am. The preselection of any of these three masses restricts the location of expected diffuse peaks to a corresponding line on the m*-E/Eo plane (Fig. 1). ...

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Letters to the editor

Cited by 7 publications

References 65 publications

Graphical aids and scanning modes for tandem mass spectrometry

Graphical aids and scanning modes for tandem mass spectrometry

Selective analysis of metastable ions

Accurate linked scans based on digital real time mass linearization and function generation

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