Fast atom bombardment-mass spectrometry FAB-MS

FIG. 14 Distribution of alkanemono- and disulfonates in a commercial product (Hostapur SAS 93) by fast atom bombardement-mass spectrometry (FAB-MS). Conditions glycerol/H20, KCI, 3-nitrobenzylalcohol. 

Numerous chromatographic methods coupled with MS have been developed for quaternary ammonium compounds. HPLC and fast atom bombardment mass spectrometry (FAB-MS) techniques have been applied to analyse concentrations of alkyldimethylbenzyl ammonium... 

Reports of depolymerization studies carried out by Semiyen and co-workers at the University of York, UK, typically used much longer reaction times (24-72 h) for the depolymerization of PET [27], This group also reported that the titanates were ineffective catalysts for depolymerization, but it is not known whether measures to prevent titanate hydrolysis were taken. The York group also reported that the relative proportions of cyclic oligomers (trimer, tetramer, etc.) altered as the dilution ratio was changed. Similar results were seen with PBT. They have also reported fast-atom bombardment mass spectrometry (FAB-MS), LC-MS, GPC and X-ray crystallography data. The most recent work reports characterization of the cyclic oligomers from six ester and ether ester systems [29],... 

The development of mass spectrometric techniques, such as fast atom bombardment mass spectrometry (FAB-MS), ° ° Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), ° and tandem mass spectrometry (MS"), ° allowed enantiodiscrimination of chiral ion-dipole complexes the gas phase. These techniques and others will be illustrated in detail in the next Section 3. 

S. J. 1992. Applications of fast atom bombardment mass spectrometry (FAB-MS) and continuous-flow FAB-MS to carotenoid analysis. Methods Enzymol. 213 322-336. 

HPLC with column switching and mass spectrometry was applied to the online determination and resolution of the enantiomers of donepezil HC1 in plasma [38]. This system employs two avidin columns and fast atom bombardment-mass spectrometry (FAB-MS). A plasma sample was injected directly into an avidin trapping column (10 mm x 4.0 mm i.d.). The plasma protein was washed out from the trapping column immediately while donepezil HC1 was retained. After the column-switching procedure, donepezil HC1 was separated enantioselectivity in an avidin analytical column. The separated donepezil HC1 enantiomers were specifically detected by FAB-MS without interference from metabolites of donepezil HC1 and plasma constituents. The limit of quantification for each enantiomer of donepezil HC1 in plasma was 1.0 ng/ml and the intra-and inter-assay RSDs for the method were less than 5.2%. The assay was validated for enantioselective pharmacokinetic studies in the dog. 

Tryptic Maps of Relaxin and Relaxin B-chain. Digestion of the A-chain of human relaxin with trypsin can theoretically result in the release of five fragments that of the B-chain in the release of six fragments as illustrated in Table II. A typical tryptic map of relaxin B-chain is shown in Figure 2. The peptide was reduced and carboxymethylated with iodoacetic acid before enzymatic digestion. The peptide assignments were made after analysis of the peaks by amino acid hydrolysis for amino acid composition and confirmed by fast atom bombardment mass spectrometry (FAB-MS) as shown in Table IH... 

The ZnCl2 system has probably been studied in the most detail. Fast atom bombardment mass spectrometry (FAB MS) has been used to identify the species present. It was found that ZnCl3, Zn2Cl5 and Zn3Cl7 species are all present in the liquids. The relative proportions of anionic species depend on the ionic liquid composition. Lecocq et al. [108] used electrospray ionization to look at the various species present and found that in Lewis basic liquids x(ZnCl2) <0.5 ZnC -whereas the di- and tri-metallate species were more prevalent in Lewis acidic liquids. 

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. 

The molecular masses of the complex compounds are conveniently determined by soft-ionization methods, such as fast atom bombardment mass spectrometry (FAB-MS), in the positive and/or negative mode. This method can easily be applied to the ionization of non-volatile, non-derivatized, polar compounds, and is particularly suited to the analysis of saponins. Extremely valuable is the use of high resolution FAB-MS (HRFAB-MS), which provides the exact mass of high molecular weight compounds, and consequently their molecular formulae. 

Dayal, B. and Salen, G. (1990). Fast atom bombardment mass spectrometry (FAB-MS) studies of conjugated bile alcohols. Presented in part at the 17th International Symposium on the Chemistry of Natural... 

This synthetic investigation confirmed the structure of the metabolite by comparison of fast atom bombardment-mass spectrometry (FAB-MS) spectra for the natural and synthetic cyclostellettamine C and for the monomeric synthetic compound 80 obtained by cyclization as indicated in Fig. (27). Additional confirmation came by comparing the bioactivities shown by synthetic dimer 55, mono-pyridinium 80 and natural cyclostellettamine C as antagonist agents for muscarinic receptors [43]. 

Several physical methods have been employed to ascertain the existence and nature of ICs infrared (IR) absorption spectroscopy nuclear magnetic resonance (NMR) spectroscopy,14 including JH nuclear Overhauser effect (NOE) difference spectroscopy, H 2-D rotating-frame Overhauser effect spectroscopy (2-D ROESY),15 and solid-state 13C cross-polarization/magic angle spinning (CP/MAS) spectroscopy 16 induced circular dichroism (ICD) absorption spectroscopy 17 powder and singlecrystal X-ray diffraction 18 and fast atom bombardment mass spectrometry (FAB MS). 

Prabhakar et al. [56] developed and validated six HPLC assay methods which permitted resolution of tailing problems for the separation of phenothiazine bioactive components and preservatives in liquid pharmaceutical formulations by using cyano-, C-8, C-18, and cation-exchange phases. The mass spectrometry (MS) of phenothiazines in biological samples is important in forensic analysis. However, since most phenothiazines having long piper-azinyl side chains are thermolabile, the phenothiazines are not suitable for conventional gas chromatography (GC)/MS analysis. Therefore, a system of capillary HPLC/fast atom bombardment-mass spectrometry (FAB-MS) was... 

Fast atom bombardment mass spectrometry (FAB-MS) is a renewed old technique that is most often thought of in terms of a relatively novel mass spectral technique. In fact, as early as in 1966, Devienne and co-workers presented data on a technique that they called molecular beam for sohd analysis (MBSA) [1]. The idea was further developed by the same group but was ignored by the rest of the scientific community until the announcement by Barber et al. [2] and by Surman and Vickerman [3] of the discovery of FAB stimulated efforts throughout the world as well as a number of international symposia and workshops devoted in whole, or in part to the understanding of FAB and its apphcations. 

The particular use of mass spectrometry techniques was of fundamental relevance in the structural determinations of CMHs from different species, including analytical variations as fast atom bombardment mass spectrometry (FAB/MS), electronspray ionization (ESI-MS) and low energy collision-induced dissociation tandem mass spectrometry (ESI-... 

Some discussion on the use of mass spectrometry for end group deteniiination can be found in recent texts."Traditionally mass speclromelric lechniques have required polymers of relatively low molecular weight. Meisters et a/." reported that fast atom bombardment mass spectrometry (FAB-MS) can be applied in the analysis of MM A oligomers to at least hexadecamer. For polymers that degrade by unzipping, pyrolysis GCMS has provided extremely useful data on initiation processes. Thus, Farina et <7/. and Ohtani et described the... 

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