FABMS spectrometry

FABMS Fast-atom bombardment mass spectrometry... 

The treatment of sucrose with anhydrous HF89 results in the formation of a complex mixture of pseudooligo- and poly-saccharides up to dp 14, which were detected by fast-atom-bombardment mass spectrometry (FABMS). Some of the smaller products were isolated and identified by comparison with the known compounds prepared86 88 a-D-Fru/-1,2 2,1 -p-D-Fru/j (1), either free or variously glucosylated, was a major product, and this is in accord with the known stability of the compound. The mechanism of formation of the products in the case of sucrose involves preliminary condensation of two fructose residues. The resultant dianhydride is then glucosylated by glucopyranosyl cation.89 The characterization of this type of compound was an important step because it has permitted an increased understanding of the chemical nature of caramels. 

Thus as a starting point for understanding the bombardment process we have developed a classical dynamics procedure to model the motion of atomic nuclei. The predictions of the classical model for the observables can be compared to the data from sputtering, spectrometry (SIMS), fast atom bombardment mass spectrometry (FABMS), and plasma desorption mass spectrometry (PDMS) experiments. In the circumstances where there is favorable agreement between the results from the classical model and experimental data It can be concluded that collision cascades are Important. The classical model then can be used to look at the microscopic processes which are not accessible from experiments In order to give us further insight into the ejection mechanisms. 

The FABMS (Fast Atom Bombardment Mass Spectrometry) technique Is reviewed In this chapter with emphasis upon laboratory Instrumentation and procedures. 

Although the FABMS (Fast Atom Bombardment Mass Spectrometry) technique has only been in use for a few short years (since 1981), it traces its roots back well over a century (1). It has been observed that the bombardment of a surface by energetic ions produces the desorption of atoms and molecules from the surface of the target. This process, known as Sputtering, produces a yield (number of atoms sputtered per incident ion) which generally increases with the energy, the mass and the incidence angle of bombardment (2). 

Secondary Ion Mass Spectrometry SIMS preceded and laid much of the groundwork used in FABMS as discussed in the Background. To come full circle a FAB apparatus on a mass spectrometer can be used to... 

It is evident from the spectra that absolute ion abundances cannot be used for quantitation. However, the ion abundance ratio of the two compounds remained constant over the selected concentration range. Therefore, internal standards must be used for quantitation by SIMS. This has been found to be true for fast-atom bombardment mass spectrometry (FABMS), also [124]. 

Fast atom bombardment mass spectrometry (FABMS) has become an important addition to the ionization techniques available to the analytical chemist in recent years. It has been particularly useful in a number of diverse applications which include molecular weight determinations at high mass, peptide and oligosaccharide sequencing, structural analysis of organic compounds, determination of salts and metal complexes, and the analysis of ionic species in aqueous solutions. This paper will focus on some aspects of the quantitative measurement of ionic species in solution. The reader is referred to a more comprehensive review for more details of some of the examples given here as well as other applications (1). 

In order to assign the disulfide bonds of these molecules fast atom bombardment mass spectrometry (FABMS) which has been used not only to confirm amino acid sequence data but also to elucidate post-translational modifications of proteins, such as disulfide bonds, has been employed. For this purpose a sample of native Er-2, containing four methionines, was subjected to CNBr cleavage and without further fractionation directly... 

Fast atom bombardment mass spectrometry (FABMS) has been used to investigate the selectivity of monocyclic crown ethers for Group IA metal cations in competition experiments (56). We applied this semiquantitative technique for the first time to bis crown ethers (51, 53) and observed that (7) and (8) in competition experiments with Li +, Na+, K+, and Cs+ exhibited exclusive selectivity for K+ (Fig. 9). Ligands (9) and (10) however displayed no preference for any particular alkali metal cation. 

Mass spectrometry is a standard spectroscopic technique for the characterisation of high molecular weight organic and inorganic compounds, but has until recently received little attention from the zeolite community. The surface composition of zeolites has been explored using fast atom bombardment mass spectrometry (FABMS)[66] and secondary ion mass spectrometry [67], but mass spectrometric analysis of the bulk composition of a zeolite or of adsorbed molecules has not until very recently been attempted. The practical difficulty is to vaporise the solid. Two different strategies have been proposed laser ablation and plasma desorption. 

As a result of this reaction, we isolated a violet product with a peak at 1284.3 by fast atomic bombardment mass spectrometry (FABMS). The mass of the molecular ion indicated the incorporation of three cobalt atoms. This result was confirmed by elemental analysis. We tried examining the oxygen-complexing ability of our salen-type complex 71, but... 

Crown ethers have been used for improving the detection of fullerenes by electrospray mass spectrometry [13]. Sawada et al. have developed a FABMS methodology for the determination of chiral recognition of amino acid esters by crown ethers [14]. This method requires that the racemic mixture of the guests contains one enantiomer in its isotoplcally labeled form. Mass spectral analysis of the molecular ion peaks for H + and H + G(5) allows a direct comparison of their relative abundances, where H and G are host and guest, respectively. 

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