Reversed-geometry, double-focusing

Double-focusing reverse geometry ion optics is a combination in which the magnet is placed before the ESA, as shown in Figure 24.6. 

Figure 1.1. Schematic of a double-focusing reverse geometry magnetic-sector instrument.

We used both icr reactivity studies and collision-induced dissociation (cid) in a ZAB-2F double-focusing, reversed-geometry mass spectrometer to study the structures of isomers (47). 

Mass spectrometer configuration. Multianalyzer instruments should be named for the analyzers in the sequence in which they are traversed by the ion beam, where B is a magnetic analyzer, E is an electrostatic analyzer, Q is a quadrupole analyzer, TOP is a time-of-flight analyzer, and ICR is an ion cyclotron resonance analyzer. For example BE mass spectrometer (reversed-geometry double-focusing instrument), BQ mass spectrometer (hybrid sector and quadrupole instrument), EBQ (double-focusing instrument followed by a quadrupole). 

When the first quadrupole of a triple quadrupole is replaced by a double-focusing mass spectrometer, the instrument is termed a hybrid (i.e. a hybrid of magnetic sector and quadrupole technologies). Figure 3.9 shows the MSi unit as a forward-geometry instrument although there is no reason why this could not be of reversed- or even tri-sector geometry. 

Mass-analysed ion kinetic energy spectrometry (MIKES) A form of MS-MS product-ion scan that may be carried out on a reversed-geometry double-focusing mass spectrometer. 

Reverse-geometry double-focusing mass spectrometer A double-focusing mass spectrometer in which the magnetic analyser precedes the electrostatic analyser. 

Figure 2. Schematic view of reversed geometry double focusing mass spectrometer used for kinetic energy release measurements.

A. The Pulsed Ionization, High-Pressure, Reverse Geometry, Double-Focusing Mass Spectrometer... 

Figure 1. Schematic of the reverse geometry double-focusing high-pressure mass spectrometer.

Figure 5.29 Instrumental setup of a radiofrequency (rf) glow discharge mass spectrometer by combining an ion source developed in house with a commercial double-focusing sector field mass spectrometer with reverse Nier-Johnson geometry (Element, Thermo Fisher Scientific, Bremen, Germany), (f S. Becker et al., IntJ. Mass Spectrom., 164, 81 (1997). Produced by permission of Elsevier.)...

Double-focusing mass spectrometer with EB configuration in which a deflection of 90° electrostatic analyser (E) is followed by a 90° magnetic analyser (B) (or reverse geometry - BE). 

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