Trapped-ion cell

Vartanian V H, Anderson J S and Laude D A 1995 Advances in trapped ion cells for Fourier transform ion cyclotron resonance mass spectrometry Mass Spec. Rev. 41 1-19... 

Caravatti, R Allemann, M. The Infinity Cell a New Trapped-Ion Cell With Radiofrequency Covered Trapping Electrodes for FT-ICR-MS. Org. Mass Spectrom. 1991,26,514-518. 

Figure 1 is a schematic of a trapped ion cell with cubic geometry, which is commonly used in FTMS (8, 11). The cell is contained... 

Figure 1. Schematic representation of a cubic trapped ion cell commonly used in FTMS. Coherent motion of ions in the cell induces an image current in the receiver plates. The time domain signal is subjected to a Fourier transform algorithm to yield a mass spectrum.

Source Cell Designation of the trapped ion cell located in the... 

Trapped Ion Cell An electrostatic-magnetic ion storage device. 

Fig. 1 Schematic drawing of a cubic FT-ICR trapped-ion cell. The side of such cells is typically ca 2.5 cm long...

Fig. 2 Typical sequence of pulses in a FT-ICR trapped-ion cell. During the trapping-time period, mass-selected ions or electrons may be ejected from the cell.

Enamine basicity has been investigated exclusively by the ICR technique, one of the most salient features of which is the low working pressures usually employed (between 10- 7 and 10- 4 torr). Drift-cell instruments allow the ion-molecule reaction to develop with thermalization of the species involved in the equilibrium in a few milliseconds at a pressure of ca 10- 4 torr. Trapped-ion cell instruments afford reaction times of up to... 

Gas-phase acidities and basicities for many organic compounds are now available, primarily due to the development within the past decades of three new experimental techniques pulsed high-pressure i.e. 0.1... 1300 Pa) mass spectrometry (HPMS) [22, 23, 118], the flowing afterglow (FA) technique with a fast-flowing gas like helium in the pressure range of ca. 10 . .. 10 Pa [119], and pulsed electron beam, trapped ion cell, ion cyclotron resonance (ICR) spectrometry, carried out at ca. 10 ... 10 Pa [24-26, 115]. 

Anderson, J. S., Vartanian, H. und Laude, D. A., Evolution of trapped ion cells in Fourier transform ion cyclotron resonance mass spectrometry. Trend. Anal. Chem. 1994,13, 234-239. 

At present, easily handled expressions which allow rapid determination of rate constants are available only for the limiting case of IMR systems with low conversion. Expressions for k derived from zero-pressure power absorptions are systematically too low. They decrease with increasing pressure and increasing residence time i . On the other hand, it does not seem entirely clear how to establish experimental ICR parameters which fulfill the conditions required by the theory 2 ). Most of the experimental uncertainties stem from pressure measurements and from determination of ion transit times in the cell. Capacitance manometers and four-sectioned cells in connection with a drift pulse technique seem better experimental equipment for the purpose of measuring rate constants of IMR. For future development the trapped-ion cell developed by Mclver iss.iso) promises some advances. The present absolute rate constants of IMR must be treated as estimates of poor accuracy. 

Preliminary FT-ICR experimentsl0"15 were performed on a prototype instrument which was developed by modification of an existing conventional trapped-ion cell ICR spectrometer. A new FT-ICR spectrometer has been constructed recently in our laboratories and all experiments described herein have been performed on this instrument. 

A block diagram of the present instrument is shown in Figure 3. The spectrometer consists of a cubic trapped-ion cell, a vacuum system (not shown), and the associated analog and digital electronics. The operation of the instrument is as follows the sample is introduced into the cell and is ionized by a short pulse from the electron beam. After a delay time that permits parent ions to react with the background neutral gas and form product ions, the cyclotron motion of all ions in the cell is coherently excited. This excitation is accom-... 

Tolmachev AV, Robinson EW, Wu S, Kang H, Lourette NM, Pasa-Tolic L, Smith RD. Trapped-ion cell with improved DC potential harmonicity for FT-ICR MS. J Am Soc Mass Spectrom 2008 19 586-597. 

McMahon TB, Beauchamp JL. A versatile trapped ion cell for ion cyclotron resonance spectroscopy. Rev Sci Instrum. 1972 43 509-12. 

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