Mass spectrometry commercial instruments

From the 1980s onwards, dedicated setups (and acronyms) have been developed, e.g., SALI (Becker and Gillen, 1984), sputter initiated resonance ionization spectrometry (SIRIS) (Parks, 1990), surface analysis by resonant ionization of sputtered atoms (SARISA, Pellin et al., 1989), and the Chicago-Argonne resonance ionization mass analysis (CHARISMA, Ma et al., 1995). The recent proliferation of commercial time-of-flight (TOP) secondary ion mass spectrometry (SIMS) instruments stimulates their conversion into SALI setups. 

Commercial Instruments Because of the proliferation of applications of mass spectrometry in organic and analytical chemistry, there are instruments marketed by numerous companies today. Some of the popular ones are the low resolution, single focusing model 21-490 and the high resolution, double focusing models, 21-492 and 21-110 of Du Pont de Nemours Co, and the double focusing model MS-9 of Associated Electrical Industries... 

Principles and Characteristics The original idea of spark-source mass spectrometry (SSMS) is due to Dempster [356], long before the first commercial instruments. In spark-source MS, atomisation and ionisation... 

Table 8.60 shows the main features of GD-MS. Whereas d.c.-GD-MS is commercial, r.f.-GD-MS lacks commercial instruments, which limits spreading. Glow discharge is much more reliable than spark-source mass spectrometry. GD-MS is particularly valuable for studies of alloys and semiconductors [371], Detection limits at the ppb level have been reported for GD-MS [372], as compared to typical values of 10 ppm for GD-AES. The quantitative performance of GD-MS is uncertain. It appears that 5 % quantitative results are possible, assuming suitable standards are available for direct comparison of ion currents [373], Sources of error that may contribute to quantitative uncertainty include sample inhomogeneity, spectral interferences, matrix differences and changes in discharge conditions. 

TOF analyzers are especially compatible with MALDI ion sources and hence are frequently coupled in aMALDI-TOF configuration. Nevertheless, many commercial mass spectrometers combine ESI with TOF with great success. For proteomics applications, the quadrupole TOF (QqTOF) hybrid instruments with their superior mass accuracy, mass range, and mass resolution are of much greater utility than simple TOF instruments.21,22 Moreover, TOF instruments feature high sensitivity because they can generate full scan data without the necessity for scanning that causes ion loss and decreased sensitivity. Linear mode TOF instruments cannot perform tandem mass spectrometry. This problem is addressed by hybrid instruments that incorporate analyzers with mass selective capability (e.g., QqTOF) in front of a TOF instrument. 

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]... 

Many applications for ion analysis use a UV detector with indirect detection, though other electrochemical, laser-induced fluorescence (LIE), or mass spectrometry detectors have been described. The main advantage of UV detection is its availability on commercial instruments and that both UV-absorbing and non-UV-absorbing analytes may be detected. Nowadays, electrochemical detectors are also available specific background electrolytes (BGEs) must be used and the detector has to be adapted to existing CE instruments. 

Carbon dioxide may be readily analyzed by various instrumental techniques, such as IR, GC, and GC/MS. Many portable infrared analyzers are available commercially for rapid, on site monitoring of CO2. Also, it can be analyzed by GC using a TCD or an FID. It readily may be identified by mass spectrometry from its characteristic ionic mass 44. Dissolved CO2 in water... 

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