Fast atom bombardment mass level

Simms etal. [8] discuss the quantitative determination of cationic surface active agents at the sub-ppb level in sewage sludges using fast atom bombardment mass spectrometry. 

The average DS as determined by these methods provides only the simplest characterization of these derivatives, and further analysis was necessary to characterize the mixture of SBE bands of different levels of substitution. Due to the presence of the anionic sulfonate substituent, it is possible to use capillary electrophoresis (23), to separate the SBE-CD substitution bands and to characterize the fingerprint of the composition (Fig. 10). Anion exchange chromatography (24) was utilized to isolate separate substitution bands (mono- to deca-derivatives) that were subsequently identified by NMR and fast atom bombardment mass spectroscopy (FAB-MS). 

RM Caprioli, SN Lin. On-line analysis of penicillin blood levels in the live rat by combined microdialysis/fast-atom bombardment mass spectrometry. Proc Natl Acad Sci USA 87 240-243,1990. 

Investigation of interfacial effects and interactions between biocompounds and transducer surfaces at the molecular and atomic levels by exploiting new methods of surface analysis (e,g scanning microscopy techniques, fast-atomic-bombardment mass spectrometry, laser-assisted mass spectrometry, time-of-flight secondary ion mass spectrometry, Fourier-transform infrared spectrometry, ellipsometry. X-ray photoelectron spectroscopy, and electron microscopy)... 

Mass Spectrometry. Mass spectrometry holds great promise for low-level toxin detection. Previous studies employed electron impact (El), desorption chemical ionization (DCI), fast atom bombardment (FAB), and cesium ion liquid secondary ion mass spectrometry (LSIMS) to generate positive or negative ion mass spectra (15-17, 21-23). Firm detection limits have yet to be reported for the brevetoxins. Preliminary results from our laboratory demonstrated that levels as low as 500 ng PbTx-2 or PbTx-3 were detected by using ammonia DCI and scans of 500-1000 amu (unpublished data). We expect significant improvement by manipulation of the DCI conditions and selected monitoring of the molecular ion or the ammonia adduction. 

A striking feature of the ILs is their low vapor pressure. This, on the other hand, is a factor hampering their investigation by MS. For example, a technique like electron impact (El) MS, based on thermal evaporation of the sample prior to ionization of the vaporized analyte by collision with an electron beam, has only rarely been applied for the analysis of this class of compounds. In contrast, nonthermal ionization methods, like fast atom bombardment (FAB), secondary ion mass spectrometry (SIMS), atmospheric pressure chemical ionization (APCI), ESI, and MALDI suit better for this purpose. Measurement on the atomic level after burning the sample in a hot plasma (up to 8000°C), as realized in inductively coupled plasma (ICP) MS, has up to now only rarely been applied in the field of IE (characterization of gold particles dissolved in IE [1]). This method will potentially attract more interest in the future, especially, when the coupling of this method with chromatographic separations becomes a routine method. 

The acetylcholine levels in rat brain regions were determined by Ikarashi et al. [196], The method used was an application of FRIT fast-atom-bombardment liquid chromatography-mass spectrometry. This technique was used to determine acetylcholine levels in seven regions of rat brain by monitoring the intact molecular cations of... 

In spite of these apparent limitation, the sequencing of polynucleotides, using FAB mass spectrometry (that produces only a few intense ions), looks very promising. Fast-atom bombardment has not yet reached the molecular-weight level of native DNA or RNA, and the ultimate answer might lie around the use of new bombardment atoms or perhaps even around the resurgence of the almost abandoned time-of-flight spectrometers. 

Mass spectra were obtained on a AEI MS9 (Manchester, U.K.) instrument equipped with a fast atom bombardment source (Figures 10 and 11). The medium was either glycerol or Cleland and the sample was introdiKxd by means of direct insertion. Instrument settings were 92-963 total scans in run, 4 sampling rate, 256 signal level threshold, 30 minimum peak width, 5 scan rate (sec/dec), 10.0. 

One of the major problems in analytical chemistry is the detection and identification of non-volatile compounds at low concentration levels. Mass spectrometry is widely used in the analysis of such compounds, providing an exact mass, and hence species identification. However, successful and unequivocal identification, and quantitative detection, relies on volatilization of the compound into the gas phase prior to injection into the analyser. This constimtes a major problem for thermally labile samples, as they rapidly decompose upon heating. In order to circumvent this difficulty, a wide range of techniques have been developed and applied to the analysis of nonvolatile species, including fast atom bombardment (FAB), field desorption (FD), laser desorption (LD), plasma desorption mass spectrometry (PDMS) and secondary-ion mass spectrometry (SIMS). Separating the steps of desorption and ionization can provide an important advantage, as it allows both processes to be... 

With the introduction of fast-atom bombardment (FAB) in 1982, and matrix-assisted laser desorption/ ionization (MALDI) and electrospray ionization (ESI), most of the biomedical applications have been directed towards these methods. The 52( f.pD method has been found to have wide applicability, including the study of refractory materials, catalysts, semiconductors and frozen gases. Electronics capable of measuring the timing of events with subnanosecond resolution (the time it takes for a single photon to travel 1 cm) is used by this method as well as event-by-event data acquisition using the computer to make decisions at the molecular level, the basis of correlation mass spectrometry, a unique feature of 252Cf-PD. 

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