Sector-quadrupoles. hybrid instruments

Magnetic sector, triple quadrupole, Q-TOF, and magnetic sector-Q hybrid instrument. 

Fig. 9.2. Tandem-in-space setups for different beam instruments (a) magnetic four-sector instmment of EB-EB geometry, (b) magnetic sector-quadrupole hybrid of EB-qQ geometry, (c) triple quadmpole (includes QqQ, QhQ, QoQ setups), and (d) ReTOF instrument.

A few examples of SID instruments are shown in Figures 3 to 6 which incorporate some or all of the considerations discussed above. Figure 3 is an off-axis large incident angle/low collision energy hybrid sector/quadrupole SID instrument of the BEEQ configuration (B = magnetic sector, E = electrostatic... 

This chapter provides brief descriptions of analyzer layouts for three hybrid instruments. More extensive treatments of sector/TOF (AutoSpec-TOF), liquid chromatography/TOF (LCT or LC/TOF with Z-spray), and quadrupole/TOF (Q/TOF), are provided in Chapters 23, 22, and 21, respectively. 

Scanning techniques are carried out differently with such hybrid instruments as the triple quadrupole analyzer, the Q/TOF (quadrupole and time-of-flight), and double magnetic-sector instruments. 

In mass spectrometers, ions are analysed according to the ml7. (mass-to-charge) value and not to the mass. While there are many possible combinations of technologies associated with a mass-spectrometry experiment, relatively few forms of mass analysis predominate. They include linear multipoles, such as the quadrupole mass filter, time-of-flight mass spectrometry, ion trapping forms of mass spectrometry, including the quadrupole ion trap and Fourier-transform ion-cyclotron resonance, and sector mass spectrometry. Hybrid instruments intend to combine the strengths of the component analysers. 

Various tandem MS instrument configurations have been developed, e.g. sector instruments, such as CBCE, CBCECB or CECBCE, and hybrid instruments, e.g. BCECQQ (B = magnetic sector analyser, E = electrostatic analyser, C = collision cell, Q = quadrupole mass spectrometer), all with specific performance. Sector mass spectrometers have been reviewed [168],... 

The most common types of MS/MS instruments available to researchers in food chemistry include triple quadrupole mass spectrometers and ion traps. Less common but commercially produced tandem mass spectrometers include magnetic sector instruments, Fourier transform ion cyclotron resonance (FTICR) mass spectrometers, and quadrupole time-of-flight (QTOF) hybrid instruments (Table A.3A.1). Beginning in 2001, TOF-TOF tandem mass spectrometers became available from instrument manufacturers. These instruments have the potential to deliver high-resolution tandem mass spectra with high speed and should be compatible with the chip-based chromatography systems now under development. 

The types of tandem mass spectrometers capable of performing MS/MS experiments fall into two basic categories tandem in space and tandem in time. Tandem-in-space instruments have discrete mass analyzers for each stage of mass spectrometry examples include multisector, triple-quadru-pole, and hybrid instruments (instruments having mixed types of analyzers such as a magnetic sector and a quadrupole). Tandem-in-time instruments have only one mass analyzer where each stage of mass spectrometry takes place in the same analyzer but is separated in time via a sequence of events. Examples of this type of instrument include Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers and quadrupole ion traps, described in Chapter 3. 

MS/MS techniques can be performed on double-focusing sector instruments as well as on quadrupole or hybrid instruments. For the purpose of this discussion will concentrate on a condensed survey of double focusing sector instruments. References that provide substantial accounts on quadrupole and hybrid instruments used for MS/MS can be found in the bibliography at the end of this chapter. 

Sector instruments and hybrid quadrupole-scctor instruments have also been u>od in a tandem manner. The first tandem mass spectrometers were sector instruments that combined an electric sector speciromc-ler with a magnetic sector spccironieier. cither in forward geometry (electric sector followed by magnetic... 

Hybrid instruments combining magnetic sector and quadrupole analyzers have been developed, which... 

Figure 3 Design of a hybrid sector-quadrupole instrument with the configuration BEqQ. FFR = field-free region.

Hybrid instruments include the BEqQ spectrometer (magnetic sector, B electric sector, E RF-only quadrupole, q quadrupole mass analyzer, Q) and the BTOF (magnetic sector, B TOF analyzer, TOF) spectrometer. The QqTOF spectrometer is similar to the triple quadrupole (QqQ) instrument except that the final quadrupole mass analyzer is replaced with a TOF analyzer. In another variant, the Qq section can be replaced by a quadrupole ion trap to yield an ion-trap-TOF instrument. 

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