Mass spectrometry magnetic sector instruments

Mass Spectrometry of Small Molecules Magnetic-Sector Instruments 409... 

R. S. Bordoli, K. Howes, R. G. Vickers, R. H. Bateman, and D. J. Harvey. Matrix-Assisted Laser Desorption Mass Spectrometry on a Magnetic Sector Instrument Fitted with an Array Detector. Rapid Commun. Mass Spectrom., 8(1994) 585-589. 

From the 1950s to the present mass spectrometry has changed tremendously and still is changing. [12,13] The pioneering mass spectrometrist had a home-built rather than a commercial instmment. This machine, typically a magnetic sector instrument with electron ionization, delivered a few mass spectra per day, provided sufficient care was taken of this delicate device. If the mass spectrometrist knew this particular instrument and understood how to interpret El spectra he or she had a substantial knowledge of mass spectrometry of that time. [14-18]... 

Quantitative Bioanalysis with High Mass Resolution Prior to the introduction of the API sources for LC-MS, GC-MS was the dominant format for mass spectrometry. Within GC-MS, mass analysis at high resolution using magnetic sector instruments was relatively common, especially in the central mass spectrometry facilities of major corporations and universities. Uses of these instruments included quantitation by GC-HRMS for improved specificity and sensitivity. 

Mass Spectrometry — The mass spectrometers and associated equipment have been described in detail (9). In brief, an LKB 9000 GLC-MS (a magnetic sector instrument) was utilized with a modified accelerating voltage alternator (AVA) (12). For A 9-THC the mass spectrometer was set to focus alternately on the ions... 

At its simplest, mass spectrometry (MS) is a technique for measuring the mass, and therefore the molecular weight (MW), of a molecule. In addition, it s often possible to gain structural information about a molecule by measuring the masses of the fragments produced when molecules are broken apart. There are several different kinds of mass spectrometers available, but one of the most common is the electron-ionization, magnetic-sector instrument shown schematically in Figure 12.1 (p. 442). 

Fig. 120. Glow discharge mass spectrometry. A Sector field based instrument (a) glow discharge source (b) magnetic sector field (c) electrostatic energy analyzer (d) Daly detector (e) ...

Identifrcation of components in the extracts was conducted by mass spectrometry. The sample was injected onto an HPS890 GC. The chromatographic conditions for the OV-1 column were the same as described for GC analysis. The end of the GC capillary column was inserted directly into the ion source of the mass spectrometer via a heated transfer line maintained at 280°C. The mass spectrometer was a Micromass Prospec high resolution, double-focusing, magnetic sector instrument. The mass spectrometer was operated in the electron ionization mode (El), scanning from ni/z 450 to m/z 33 at 0.3 seconds per decade. 

Accurate mass measurements are often used for the identification or confirmation of the molecular formulas of drug metabolites. The analytical utility of high resolution mass spectrometry began with the introduction of double-focusing magnetic sector instruments, which could routinely achieve... 

T. J. P. Naven and D. J. Harvey, Effect of structure on the signal strength of oligosaccharides in matrix-assisted laser desorption/ionization mass spectrometry on time-of-flight and magnetic sector instruments. Rapid. Commun. Mass Spectrom., 10 (1996) 1361-1366. 

Special mass spectrometry systems are built for isotope ratio measurements. Most isotope ratio mass spectrometers consist of a single-focusing magnetic sector instrument and a multiple Faraday cup detection system. Because the Faraday cup exhibits a stable response, it is an ideal detector for isotope ratio measurements. Simultaneous collection of relevant ion beams from all isotopes provides high-precision isotopic measurements. A three-Faraday cup detection system is shown in Figure 7.9. The multicup assembly is placed at the focal plane of the mass analyzer and can be used for the simultaneous detection of each isotopic form of the analyte species (e.g., m/z 44, 45, and 46 from CO2). Commercial instruments with up to nine collectors are available. 

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