Analyzers, mass quadrupole

Q/TOF, used for two mass analyzers (quadrupole and time-of-flight) used in combination QQQ (or QqQ)- a triple quadrupole analyzer (if q is used, it means the central quadrupole is also a collision cell)... 

Fig. 1.18 Schematic of a triple quadrupole instrument. Stage qO focusing quadrupole Ql, Q3 mass analyzing quadrupoles q2 collision cell. In the present configuration the collision energy (CE) is determined by the potential difference between qO and q2.

An impressive diversity of mass analyzers are utilized in modem analytical instrumentation. An overview of the common mass spectrometer analyzers follows, with particular emphasis on linear quadrupole mass analyzers, quadrupole ion traps, and time-of-flight mass analyzers, as they arguably constitute the quantitative MS workhorses of the pharmaceutical industry. The description of alternate analyzer systems should provide a framework in which the utility of these three particular systems provides the most cost-effective analytical mass spectrometer systems for pharmaceutical analysis. 

Quadrupole ion trap mass analyzers merge the trapping characteristics of the ICR with the physical principles of the linear quadrupole mass analyzer. Quadrupole ion traps produce time-dependent spectra with excellent sensitivity and tandem mass spectrometry capabilities, but unlike the ICR they provide these ion trapping characteristics with physically smaller and considerably less expensive instrumentation, giving them a reputation as a powerful and accessible tool for both qualitative and quantitative mass spectrometry [43-47]. The capability of quadrupole ion traps to be configured with either internal and external ionization sources has expanded their utility for modem analytical applications [48—52]. 

FIGURE 8.12 Schematic of triple quadrupole instrument, Qi and Q3 mass analyzing quadrupoles, q2 collision cell. 

Mass analyzer quadrupole (VSW mass analyst quadrupole). 

MS was first successfully applied to analysis of intact microor nisms more than 40 years ago (Anhalt and Fenselau 1975). These efforts have expanded and have been particularly significant after the introduction of the soft ionization MS techniques—matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) (Perm et al. 1989 Tanaka 2003 Karas andHillenkamp 1988). Both techniques (recognized by the Nobel Prize in Chemistry in 2002) allow the ionization and transfer into vacuum of large, intact, nonvolatile biomolecules, such as proteins. Various types of mass analyzers—quadrupole, ion trap, time-of-flight (TOF)— have been coupled to both MALDI and ESI ion sources, allowing multiple stages (tandem) MS to be performed for structure elucidation of analytes of interest. All these instrumental developments have allowed MS to become a well-established... 

Figure 8.6 Schematic diagrams for the ICP/SIFT (top) and Elan 6100DRC (bottom) instruments. In the ICP/SIFT instrument ions are produced in a plasma source and sampled by a standard atmosphere-vacuum interface (see text). The ion of interest is mass-selected in Q1, after which it is passed to the flow tube via a Venturi inlet. The flow tube is kept at a constant pressure of 0.35 Torr. Thermalized ions react with a neutral admitted at the reagent inlet as they flow downstream (to the right). Product ions are mass analyzed by Q2. In the Elan 6100DRC, ions are produced and sampled as above but are then reacted in a bandpass quadrupole reaction cell (DRC). Unreacted ions and product ions are detected by the mass analyzer quadrupole.

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