Triple-sector quadrupole tandem mass analysers

Different mass analysers can be combined with the electrospray ionization source to effect analysis. These include magnetic sector analysers, quadrupole filter (Q), quadrupole ion trap (QIT), time of flight (TOF), and more recently the Fourrier transform ion cyclotron resonance (FTICR) mass analysers. Tandem mass spectrometry can also be effected by combining one or more mass analysers in tandem, as in a triple quadrupole or a QTOF. The first analyzer is usually used as a mass filter to select parent ions that can be fragmented and analyzed by subsequent analysers. 

Fig. 5 Statistical evaluation of LC-MS-based methods for tropane alkaloids referred in this chapter. (a) Relative frequency of ionization methods. +APCI positive atmospheric pressure chemical ionization, +ESI positive electrospray ionization, FAB fast atom bombardment, +TSP positive thermospray, (b) Relative frequency of scan modes used. MS full scan MS, MS/MS tandem mass spectrometry (product ion scan), MRM multiple reaction monitoring, SIM selected ion monitoring, (c) Relative frequency of mass analysers used. EBQtQ2 double focusing sector field mass spectrometer, IT ion trap, QqQ triple quadrupole, SQ single quadrupole. Considered publications were found by PubMed data-based search and references cited in these articles...

A scan in a tandem mass spectrometer with two or more mtz analysers e.g a triple quadrupole or a sector mass spectrometer that incorporates at least one magnetic sector and one electric sector. Two or more of the analysers are scanned simultaneously so as to preserve a predetermined relationship between scan parameters to produce a product ion, precursor ion or constant neutral loss or gain spectrum. 

Tandem mass spectrometry is applicable to all types of biomolecules but typically requires specialized mass spectrometry instrumentation for implementation. The most common tandem mass spectrometer is a triple quadrupole instrument, wherein the first and third quadrupoles are used as mass analysers and the middle quadrupole is used as a collision chamber. MS/MS can be performed with double focusing sector instruments and in some cases with specialized TOF mass analysers. Quadrupole ion traps and FTICR mass spectrometers are ideally suited for MS/MS experiments, and due to the operational characteristics of these mass analysers... 

The first hyphenated approach to be considered is the on-line combination of MS and MS, i.e. tandem mass spectrometry (MS-MS). A variety of combinations of different mass analysers have been described, including quadrupole and magnetic-sector analysers as MS], and quadrupole, magnetic-sector, ion-trap and time-of-flight analysers as MS2. Instruments like triple-quadrupoles are widely used for MS-MS, either as stand-alone systems with sample introduction via a solids insertion probe or flow-injection analysis, or in on-line combination with GC or LC. The work of Yost and co-workers and of Hunt and colleagues exemplify these methods. 

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