Mass Analysis System

The time-of-flight (ToF) analyzer is the most widely used analyzer in static SIMS. As its name indicates, for this analyzer the flight time of an ion is the parameter for measurement. When ions are obtained with a constant kinetic energy from an acceleration potential (V) of 3-8 kV, the flight time of ions through a distance (L) of flight tube to reach a detector is calculated. 

20 M between 2.7 M between each ring each ring 

Mass Analyzer Mass resolution Range of Mass detection Transmission Manner of detection Relative sensitivity 

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SIMS requires an ultra-high vacuum environment, similar to AES and XPS. The ultra-high vacuum environment ensures that trajectories of ions remain undisturbed during SIMS surface analysis. The SIMS vacuum chamber and pumping system is not much different from that for AES and XPS. Figure 8.5 illustrates common SIMS structure in a vacuum chamber in which there are two main components a primary ion system and a mass analyzer system. The primary ion system includes a primary ion source, a Wien filter and ion beam deflector. The mass analysis system includes a secondary ion extractor filter, mass analyzer and ion detector. 

A mass spectrometer also using a radioactive ionizing medium has been described by Yang and Conway. Gases at pressures up to 10 Torr were irradiated by the 400-mCi tritium source in a flow system. The time required by the gas to reach the ion sampling orifice leading to the low-pressure electrode and mass analysis system was about 1 msec. The relatively... 

Mass and energy balances are used to evaluate blast furnace performance. Many companies now use sophisticated computeri2ed data acquisition and analysis systems to automatically gather the required data for daily calculation of the mass and heat balances. Typical mass and heat balances are shown in Figure 4 and Table 5, respectively. 

M. J. Tomlinson and C. L. Wilkins, Evaluation of a semi-automated multidimensional gas chromatography-infared-mass spectrometry system for initant analysis , ]. High Resolut. Chromatogr. 21 347-354 (1998). 

The low energy ions leaving the reaction chamber are re-accelerated for conventional mass analysis. Many of these instruments use a pair of quadrupole lenses (13) following re-acceleration to increase the intensity of secondary ions. Such a lens system is particularly well adapted to this application because of its large physical size and strong focussing properties. 

Direct solid-state polymer/additive mass analysis has involved various ionisation modes El (Section 6.2.1), Cl (Section 6.2.2), DCI (Section 6.2.2.1), FAB (Section 6.2.4), FI (Section 6.2.5), FD (Section 6.2.6) and LD. Survey mass spectra obtained with soft ionisation methods (FI-MS, CI-MS) provide diagnostic overviews of chemical composition. The supplemental tandem (MS/MS) and atomic composition (AC-MS) techniques are used to make specific identifications of various organic ingredients. Direct analysis of polymer systems for more than a few thousand daltons has only just begun. Ionisation methods employed are FD, ESI and MALDI. Solid-probe ToF-MS (or DI-HRMS) is a breakthrough [188]. 

COUPLED MULTIDIMENSIONAL CHROMATOGRAPHY AND TANDEM MASS SPECTROMETRY SYSTEMS FOR COMPLEX PEPTIDE MIXTURE ANALYSIS... 

D. Figeys, S.P. Gygi, G. McKinnon, and R. Aebersold, An integrated microfluidics tandem mass spectrometry system for automated protein analysis. Anal. Chem. 70, 3728-3734 (1998). 

We consider the problem of s-state energy shift according to the perturbation theory. Such analysis was performed for the pionic hydrogen in Ref. (Lyubovitskji and Rusetsky, 2000). Let Ho + Hc be the unperturbed Hamiltonian, whereas V is considered as a perturbation. The ground-state solution of the unperturbed Schrodinger equation in the center of mass (CM) system frame (E — Ho — Hc) To(0)) = 0, with E = M + m + E, is given by... 

Korfmacher, W. A. et al. 1999. Development of an automated mass spectrometry system for the quantitative analysis of liver microsomal incubation samples A tool for rapid screening of new compounds for metabolic stability. Rapid Commun. Mass Spectrom. 13 901. 

Hsieh Y., 2004. Using mass spectrometry for drug metabolism studies, in Direct Plasma Analysis Systems, Korfmacher, W.A., Ed., Boca Raton, FL, CRC Press, Chap. 5. 

This basically means that two instruments have been linked together. The first analyser can replace the traditional chromatographic separation step and is used to produce ions of chosen m/z values. Each of the selected ions is then fragmented by collision with a gas, and mass analysis of these product ions effected in the second analyser. The resulting mass spectrum is used for their identification. The potential combinations of the various magnetic sector and quadrupole instruments to form such coupled systems is considerable. Ion traps may also be operated in a tandem MS mode. 

The total ion current (TIC) can either be measured by a hardware TIC monitor before mass analysis, or it can be reconstructed by the data system from the spectra after mass analysis. [27] Thus, the TIC represents a measure of the overall intensity of ion production or of mass spectral output as a function of time, respectively. The TIC obtained by means of data reduction, [28] i.e., by mathematical construction from the mass spectra as successively acquired while the sample evaporates, is also termed total ion chromatogram (TIC). For this purpose, the sum of all ion intensities belonging to each of the spectra is plotted as a function of time or scan number, respectively. 

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