Tandem quadrupole-Fourier transform mass spectrometry

D. F. Hunt, J. Shabanowitz, R. T. Mclver, Jr., R. L. Hunter, and J. E. P. Syka, "Ionization and Mass Analysis of Nonvolatile Compounds by Particle Bombardment Tandem-Quadrupole Fourier Transform Mass Spectrometry," Anal. Chem., 57, 765-768 (1985). 

Laser-microprobe mass spectrometers are used for the study of solid surfaces. Ablation of the surface is accomplished with a high-power, pulsed laser, usually a Nd-YAG laser. After frequency quadrupling, theNd-YAG laser can produce 266-nm radiation focused to a spot as small as 0.5 pm. The power density of the radiation within this spot can be as high as 10to 10" W/cm. On ablation of the surface a small fraction of the atoms are ionized. The ions produced are accel crated and then analyzed, usually by tlme-of-flight mass spectrometry. In some cases laser microprobes have been combined with quadrupole ion traps and with Fourier transform mass spectrometers. Laser-microprobe tandem mass spectrometry is also receiv-... 

Multiple mass analyzers exist that can perform tandem mass spectrometry. Some use a tandem-in-space configuration, such as the triple quadrupole mass analyzers illustrated (Fig.3.9). Others use a tandem-in-time configuration and include instruments such as ion-traps (ITMS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS or FTMS). A triple quadrupole mass spectrometer can only perform the tandem process once for an isolated precursor ion (e.g., MS/MS), but trapping or tandem-in-time instruments can perform repetitive tandem mass spectrometry (MS ), thus adding n 1 degrees of structural characterization and elucidation. When an ion-trap is combined with HPLC and photodiode array detection, the net result is a profiling tool that is a powerful tool for both metabolite profiling and metabolite identification. 

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. 

IM has been coupled with a range of mass spectrometers. Both electrospray ionization (ESI) [21,22], and matrix-assisted laser desorption/ionization (MALDI) [18] ionization sources have been used to generate ions prior to IM analysis. Different configurations of mass analyzers have been used to perform mass analysis including quadrupole mass analyzers [23], time-of-flight (TOE) analyzers [24] and Fourier transform ion cyclotron resonance spectrometry (FT-ICR) [25]. Recently, an instrument utilizing two and three drift cells in tandem has been described [26]. 

Recently introduced tandem mass spectrometers, having both features, such as quad-rupole linear ion trap (QqLIT, LTQ or Q-trap), quadrupole time-of-fiight (QqTOF), LTQ-Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), and LTQ-Orbitrap, and so on, have allowed for the development of several new methods for acrylamide detection [107,108]. 

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