Fast-atom bombardment mass spectrum

Proton nmr titration experiments of [26] and [27] with KPF6 in acetonitrile revealed that in solution both compounds form 1 1 intramolecular sandwich complexes with the potassium cation. A number of alkyl-, vinyl- and azo-linked bis(benzo-15-crown-5) ligands are well known to exhibit this mode of K+ coordination. In the case of [26], a solid-state potassium complex was isolated whose elemental analysis and fast-atom bombardment mass spectrum ([26] K+ = 1083 complex ion) was in agreement with 1 1 complex stoichiometry (Fig. 20). 

References are given for spectroscopic studies, other v,c-oi IR hen these studies are reported in the synthetic/structural reference no further reference number is given. MS, mass spectrum FABMS, fast atom bombardment mass spectrum VT, variable-temperature. 

Figure 7. Fast atom bombardment mass spectrum of indapamide.

Figure 4, Fast atom bombardment mass spectrum of the diglutathtone conjugate of phenylalanine mustard (jM).

FIGURE 9.9 Example of a partial negative-ion fast atom bombardment mass spectrum of the total solvent extract from a marine bacterium showing phospholipid molecular species. Abbreviations PE, phosphatidylethanolamine PG, phosphatidylglycerol. 

The low-resolution mass spectrum of Indinavir sulfate was measured using fast atom bombardment mass spectrometry on a JEOL HXl lOA mass spectrometer set at a resolution of 5000. The sample was ionized from a 5 1 dithiothreitol dithioerythritol matrix using xenon as the FAB gas. The low-resolution mass spectrum [12] ofindinavir is shown in Figure 14, while the structures of the structurally significant fragment ions are illustrated in Figure 15. 

Fast atom bombardment mass spectroscopy has proved to be most useful when applied to the characterization of heteronuclear gold cluster compounds containing hydride ligands (137,149,155). Characterization is aided by the observation that peaks are invariably present in the spectrum corresponding to ions that contain all of the hydride... 

General (PAF and lysoPAF). The basic objective here is to examine the spectrum of a PAF sample subjected to fast atom bombardment-mass spectrometry (FAB-MS). The predominant feature of the resulting spectrum is the formation of a protonated mass ion. In actual fact, there is some cleavage of the molecule, but it is not extensive. These ions can, however, be used for diagnostic purposes. 

Clay, K. L., Sterre, D. O., and Murphy, R. C. (1984) Quantitative analysis of platelet activating factor (AGEPC) by fast atom bombardment mass spectrometry, Bio-med. Mass Spectrum 11, 47-49. 

Several non-volatile ionic complexes of As and Sb have been characterized by fast atom bombardment mass spectrometry (Table 12). The mass spectrum of 53 (a mixture of 3-nitrobenzyl alcohol with CH2CI2 was used as the matrix) exhibits (M -I- BF2), M, (M - 2CO)- -, CpFe(CO)2 +, Cp2Fe+ and Bi-" ions ... 

Metabolite M4 was analyzed by thermospray LC/MS (Fig. 5a) and produced a protonated molecular ion at m/z 497, 499 (confirmed by fast atom bombardment mass spectral analysis). This mass spectrum, as well as proton NMR analysis (not shown) was consistent with the acyl carnitine conjugate of the parent. Fragmentation occurred via loss of the carnitine moiety to give m/z 371, 373 the fragment ion at m/z 455, 457 could correspond to an... 

Ritterazine F (31), [a]D 59° (CH3OH), showed an (M + H)+ ion at m/z 899.5764 in the high resolution positive fast atom bombardment mass (HR-FAB )+ve spectrum, which agreed with the molecular formula C54H79N2O9. The gross structure of 31 was similar to that of ritterazine B (27). However, the NMR data of the compounds were different in the chemical shift region of C-22. The stereochemistry C-22S was assigned on the basis of the ROESY data. 

In these laboratories we have recently employed Fast Atom Bombardment Mass Spectrometry for analysis of CMEs. Depth penetrations of 1 nm per minute can be achieved, depending on beam intensity. The low penetration rate allows for excellent depth profiling studies to be carried out. Examples of FAB mass spectra obtained from a modified electrode surface are shown in Figures 5.5-5.6. This technique holds much promise for the future, since a mass spectrum of the electrode surface can be obtained. 

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