Double-focusing analyzer

Double-focusing analyzer. A magnetic analyzer and an electrostatic analyzer combined in either sequence to effect direction and velocity focusing. 

Another example of the analytical utility of the sample compaction methodology for GD-MS is work by Wayne [44] that used a Kratos double-focusing analyzer for the analysis of precious metals deposited on cordierite supports (i.e., automotive catalysts). Spectral interferences from TaO species on the target palladium, rhodium, and platinum analytes made aluminum a better choice as the matrix element. Because the Kratos instrument does not have cryogenic cooling... 

Double-focusing analyzer. A magnetic analyzer and an electrostatic analyzer combined in either ------sequence to effect direction and velocity focusing.------------------------------... 

The most popular mass analyzers for ICP-MS have been quadrapole, magnetic-sector, and double-focusing analyzers, although time-of-flight analyzers are also used. These analyzers vary in resolution, throughput, and scanning time. The resolution of a mass analyzer is defined as ... 

High-resolution mass analyzers, such as double-focusing analyzers, can reduce or eliminate many spectral interferences in ICP-MS. 

Analyzers The mass analyzer separates the ions according to their miz values. The most common analyzers are listed in Table 31-3. The most common analyzers for GC/MS are the quadrupole mass filter and the ion trap. High-resolution mass spectrometers use the double-focusing analyzer, the ion-cyclotron resonance analyzer, or the time-of-flight analyzer. 

An essential part of the double-focusing analyzer is a magnetic sector, an electromagnet with a well-defined geometry. Ions are ejected from an ion source by the action of an acceleration field. Their potential energy is fully transformed in kinetic energy... 

The double-focusing combination of electrostatic- and magnetic-sector analyzers allows the inherent energy spread of the beam to be compensated for by design and ensures that there is no spread in the beam at the collector. 

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). 

Neir-Johnson geometry. An arrangement for a double-focusing mass spectrometer in which a deflection of nil radians in a radial electrostatic-field analyzer is followed by a magnetic deflection of 7t/3 radians. The electrostatic analyzer uses a symmetrical object-image arrangement, while the magnetic analyzer is used asymmetrically. 

Electrostatic Analyzer In magnetic-sector instruments, an electrostatic sector can be incorporated either before or after the magnet to provide energy resolution and directional focusing of the ion beam. The resolution achievable in these double-focusing instruments is sufficient to separate ions having the same nominal mass (e.g., 28 Daltons) but with different chemical formula (e.g., N2 and CO). 

All analyzers use one or more of three basic principles (a) magnetic analysis, (b) electrostatic analysis, and (c) time-of-flight analysis. Magnetic analyzers of single and double focusing types are by far the most common ones currently in use, and will serve to illustrate the methods of analysis. Two other types of analyzers which have gained popularity for analytical applications but are omitted in the fol-... 

Nier-Johnson double-focusing mass analyzer. 

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