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Center quadrupole

As ions move away from the center of the quadrupole, the force experienced increases, driving them back towards the center. Quadrupoles are therefore focusing devices as well as mass filters. [Pg.70]

The most widely used tandem mass analyzer for bioanalysis is the triple-quadrupole mass spectrometer (TQMS). In the TQMS format, a characteristic fragmentation transition is monitored for an analyte with more than one mass filter in combination, hence the term MS/MS. A diagram of a TQMS is presented in Figure 11.2. A TQMS consists of two mass selecting quadrupoles, Qi and Q3, and flanked by a center quadrupole (Q2) that acts as a collision cell. Since Q2 is operated in the RF-only mode, mass selection is not performed in this region. The Q2 rods are important, however, since they refocus ions... [Pg.321]

The reactivity of the propargylium form and the nonreactivity of the cyclopropenylium form of CgHg toward acetylene led to development of a new mass spectrometric technique for the differentiation of structural isomers. In collaboration (37) with Drs. Yost and Fetterolf in our department we have used reactive collisions of low kinetic energy ions in the center quadrupole of a triple quadrupole mass spectrometer to differentiate between the two isomeric forms of CgHg . ions were formed by electron... [Pg.54]

The precursor ion selection, fragmentation, and product ion analysis can be separated in space or in time, as shown in Figure 1.29. Separation in time requires trapped ions, as available in the quadrupole ion trap or the ion cyclotron resonance trap. Separation in space necessitates at least two physically distinct mass analyzing devices, one for precursor ion selection (MS-1) and one for product ion analysis (MS-2). The simplest in-space tandem instruments are the triple quadrupole mass spectrometer (QqQ), the double-focusing sector tandem mass spectrometer (EB or BE), and the reflectron time-of-flight mass spectrometer. In a triple quadrupole, the first and third quadrupoles (Q) are mass analyzers, while the center quadrupole iq) serves as the collision cell. In sector instruments, a collision cell is situated... [Pg.44]

Dolnikowski, G.G. Kristo, M.J. Enke, C.G. Watson, J.T. Ion trapping technique forion molecule reaction studies in the center quadrupole of a triple quadrupole mass spectrometer. Int. J. Mass Spectrom. Ion Processes 1988, 82, 1-15. [Pg.28]

G.G. Dolnikowsld, M.J. Kristo, C.G. Enke, and J.T. Watson, Ion-Trapping Technique for lon/Molecule Reaction Studies in the Center Quadrupole of a Triple Quadrupole Mass Spectrometer , Int. J. Mass Spectr. Ion Proc. 82, 1 (1988). [Pg.196]

Many molecules, such as carbon monoxide, have unique dipole moments. Molecules with a center of inversion, such as carbon dioxide, will have a dipole moment that is zero by symmetry and a unique quadrupole moment. Molecules of Td symmetry, such as methane, have a zero dipole and quadrupole moment and a unique octupole moment. Likewise, molecules of octahedral symmetry will have a unique hexadecapole moment. [Pg.110]

Quadrupoles. The quadmpole mass filter (16,17), which became available commercially in 1967, consists of four cylindrical rods having circular or, more recentiy, hyperboHc cross sections, arranged with their centers on the perimeter of a circle of radius Tq. Figure 2 is a schematic diagram of a... [Pg.540]

In a conventional Fe Mossbauer experiment with a powder sample, one would observe a so-called quadrupole doublet with two resonance lines of equal intensities. The separation of the lines, as given by (4.36), represents the quadrupole splitting The parameter Afg is of immense importance for chemical applications of the Mossbauer effect. It provides information about bond properties and local symmetry of the iron site. Since the quadrupole interaction does not alter the mean energy of the nuclear ground and excited states, the isomer shift S can also be derived from the spectrum it is given by the shift of the center of the quadrupole spectrum from zero velocity. [Pg.93]


See other pages where Center quadrupole is mentioned: [Pg.831]    [Pg.383]    [Pg.735]    [Pg.64]    [Pg.65]    [Pg.641]    [Pg.745]    [Pg.663]    [Pg.831]    [Pg.383]    [Pg.735]    [Pg.64]    [Pg.65]    [Pg.641]    [Pg.745]    [Pg.663]    [Pg.287]    [Pg.287]    [Pg.373]    [Pg.110]    [Pg.86]    [Pg.222]    [Pg.7]    [Pg.194]    [Pg.371]    [Pg.414]    [Pg.22]    [Pg.227]    [Pg.374]    [Pg.375]    [Pg.391]    [Pg.433]    [Pg.229]    [Pg.205]    [Pg.520]    [Pg.89]    [Pg.170]    [Pg.183]    [Pg.400]    [Pg.408]    [Pg.433]    [Pg.445]    [Pg.271]    [Pg.228]    [Pg.147]    [Pg.164]    [Pg.343]   
See also in sourсe #XX -- [ Pg.2 , Pg.321 ]




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