Ion trap technique

H. G. Dehmelt (University of Washington, Seattle) and W. Paul (Bonn) development of the ion trap technique. 

Considerable insight about fundamental aspects of the behavior of simple Ge, Sn and Pb species can be obtained from studies aimed at characterizing the reactivity of gas-phase ions. Reactions of the primary ions obtained by electron ionization of GelTj with the neutral monogermane precursor have been characterized both by low- and high-pressure mass spectrometric techniques , and more recently by ion trap techniques (ITMS). The ability to select a particular isotopic species (usually the Ge-containing ion) in low pressure studies carried out by Fourier Transform Mass Spectrometry (FTMS) has been essential in understanding the mechanism of these processes. The main results can be summarized as follows ... 

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. 

In contrast to previous texts, which have concentrated generally on a single or limited range of ion trapping techniques, a key feature of this compilation of contributions is its coverage of all the ion trapping techniques currently in use. Spanning sixteen chapters, the text examines ... 

Volume rv is entitled Theory and Instrumentation and is composed of six parts Fundamentals, New Ion Trapping Techniques, Fourier Transform Mass Spectrometry, Quadrupole Rod Sets, 3D-Quadrupole Ion Trap Mass Spectrometry, and Photochemistry of Trapped Ions. 

Fourier transform ion-cyclotron resonance mass spectrometry (FT-ICR-MS) is also an ion-trap technique. The concept of ICR spectroscopy was first described in 1930 by Lawrence and Edlefsen [55] and was later developed as a mass... 

Of the cationically-polymerizable cyclic acetals, 1-3-dioxolan has received the most attention. By means of an ion-trapping technique, quantitative measurements of the concentration of active centres have been made and correlated with initiator incorporation to confirm the living characteristics of the linear polymers under certain conditions. The oxycarbenium ion nature of these propagating centres has been verified by C-n.m.r. spectroscopy. Methyl substitution alters the polymerizability of the homologous 1,3-dioxepanes significantly and steric hindrance in the initiator can influence both the homopolymerization and copolymerization of cyclic acetals. ... 

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). 

Superimposed on the plot of kg vs. [C] in Fig. 1 are some of the experimental techniques used to study ion-molecule association reactions in the laboratory. The low pressure ion trap technique (designated TRAP) of Dunn and co-workers (see, e.g. Barlow, Dunn, and Schauer 1984a,b) operates at sufficiendy low densities that there is no doubt that only radiative association is being observed. Unfortunately, these experiments are difficult and only a few have been performed. In only one - the radiative association reaction between CH3" and H2 (Barlow, Dunn, and Schauer 1984a,b) - was an actual value rather than an upper limit determined. A strength of this technique is that it can be utilized at temperatures as low as 10 K if H2 is used as the neutral reactant. 

We will first describe spectroscopy on collimated atomic beams and on kinematically compressed ion beams. Two groups of nonlinear spectroscopic tecliniques will be discussed saturation techniques and two-photon absorption techniques. We will also deal with the optical analogy to the Ramsey fringe technique (Sect. 7.1.2). In a subsequent section (Sect. 9.8) laser cooling and atom- and ion-trap techniques will be discussed. Here, the particles are basically brought to rest, ehminating the Doppler as well as the transit broadening effects. 

To date, no fewer than five Nobel Prizes have been awarded for work directly related to mass spectrometry J. J. Thomson (Physics, 1906) for theoretical and experimental investigations on the conduction of electricity by gases F. W. Aston (Chemistry, 1922) for discovery, by means of a mass spectrograph, of isotopes, in a large number of nonradioactive elements W. Paul (Physics, 1989) for the development of the ion trap technique and most recently J. B. Fenn and K. Tanaka (Chemistry, 2002) for the development of soft desorption ionization methods for mass spectrometric analyses of biological macromolecules. ... 

Figure 2.234 GC-MS/MS techniques. Tandem-in-space triple-quadrupole technique and tandem-in-time ion trap technique.

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