Fast atom bombardment mass spectrometry of carbobenzyloxy-protected amino acids and peptides

The positive fast atom bombardment (FAB) mass spectra of 15 N-carbobenzyloxy derivatives of α-amino acids are presented together with those of some synthetic peptides containing other widely employed protecting groups. The data obtained allow a fragmentation pattern to be established for the N-carbobenzyloxy moiety and to obtain detailed structural information on the main fragment ions. A study of the ion current ratio vs. time pattern shows that important fragments derive from the parent protonated molecule through FAB-induced condensed-phase reactions.     

Fast atom bombardment mass spectrometry of polyglycols

Fast atom bombardment mass spectrometry (FAB-MS) has rapidly become established, after its introduction two years ago, as a method of choice for mass spectral analysis of higher molecular weight polar organic chemicals. In industrial analysis, the technique has been found to be a very effective method for analyzing numerous classes of polar polymeric chemicals, including rubber and plastic additives, organometallics, and polar polymers. Normally applied in conjunction with field desorption (FD-MS), FAB-MS is used to determine chemical structures for both pure compounds and oligomeric mixtures. Fast atom bombardment results for poly(ethylene glycol) and poly(propylene glycol) show that, while oligomer quasimolecular ion distributions give a rough indication of relative oligomer abundances, the data are not quantitative in comparison with that previously described for FD-MS (or electrohydrodynamic ionization, EH-MS) analysis. More specifically, lower mass oligomer intensities tend to be too high in FAB-MS due to fragmentation reactions.     

Fast atom bombardment mass spectrometry of salts

The positive and negative fast atom bombrdment spectra of two groups of simple salts have been recorded. The structures of the major ionic species of eight chlorides and five, complex anion, sodium salts have been interpreted and tabulated.     

Fast atom bombardment mass spectrometry of pertechnetate

Negative Ion Fast Atom Bombardment Mass Spectrometry is conducted on potassium pertechnetate evaporated onto a copper probe. The mass spectra of pertechnetate /TcO ₄ ^– / reveal the presence of mononuclear and polynuclear technetium oxo species which form general series Tc_nO _n+1 ^– ,...Tc_nO_n+4 with n=1 to 5. The polynuclear species are believed to be formed via gas phase reactions.     

Fast atom bombardment mass spectrometry of coordination compounds

It is shown that fast atom bombardment mass spectrometry is well suited for the study of coordination compounds.     

Fast atom bombardment mass spectrometry of butyloxycarbonyl protected (BOC) amino acids

The positive and negative ion mass spectra of a series of BOC-protected amino acids have been obtained using an FAB source. The spectra show characteristic features including a McLafferty type of rearrangement.     

Fast atom bombardment mass spectrometry of two isomeric tripeptides

Fast atom bombardment of solids is presented as the basis of a new ion source for mass spectrometry. This novel technique is particularly useful for obtaining mass spectra from involatile and thermally labile materials. The ion source produces both positive and negative ions with equal facility, and examples of both are presented for two underivatized tripeptides. The normal second field free region metastables are observed in a double focusing mass spectrometer and comprehensive metastable pathways have been traced using Barber-Elliott (V-scan) techniques.     

Negative-ion fast atom bombardment mass spectrometry of N-phosphoamino acids

The fragmentation patterns of N-phosphoamino acids in negative-ion fast atom bombardment mass spectrometry (FABMS) showed different characteristics to those in positive-ion FABMS. Six typical N-diisopropyloxyphorphorylamino acids all had intense [M ? 1]^? peaks, and they underwent similar fragmentation pathways. In general, the elimination of one alkene molecule followed by the loss of one molecule of alcohol occurred. They also favoured an N → O rearrangement reaction, followed by fragmentation to (RO)₂ PO₂^? and (RO) (HO)PO₂^?.     

Fast atom bombardment mass spectrometry of seryl- and O-phosphoseryl-containing peptides

FAB-MS was found to be a mild technique for the rapid identification of O—phosphoseryl residues in peptides and the characterization of O—phosphoseryl—containing peptides.     

Fast atom bombardment mass spectrometry of some alkoxv- and chloro-silanes

The positive and negative FAB mass spectra of a series of alkoxy- and chloro-silanes X_m(CH₃)₃-_mSi(CH₂)_nR [m = 1 or 3, n = 3, 10 or 17, X = Cl or OMe or OEt, R = Me, NH₂, glycidoxy, COOMe, NHCO(CH₂)₇COOMe or NHCO(CH₂)₁₀CH₂OAc] were recorded in NBA and NPOE matrices. The chlorosilanes underwent rapid hydrolysis into silanols which condense to form siloxanes, the process being complete in NBA and partial in NPOE, yielding siloxane-based fragment ions in the positive spectra and silyloxyanions in the negative spectra. The alkoxysilanes were more resistant to hydrolysis, affording abundant [MH – HX]⁺ ions (X = OMe or OEt) in their positive FAB spectra and moderate to high intensity [M – H]^? ions in the negative mode, the latter undergoing characteristic sequential loss of C₂H₄, EtOH and C₂H₄. Significant variations were observed in the positive spectra of all the silanes with change of matrix.     

Fast atom bombardment mass spectrometry of protein and carbohydrate biopolymers

Within the past decade significant advances in the field of biological mass spectrometry have resulted in unique approaches to the structural analysis of biopolymers. This article pinpoints key instrumental developments and outlines strategies based upon high field fast atom bombardment mass spectrometry which are allowing hitherto elusive biopolymer structural data to be obtained.     

Fast atom bombardment in mass spectrometry: Method and applications

The review article is devoted to the mass spectrometry method of ionization of material by fast atom bombardment (FAB). The FAB method extends the possibilities of mass spectrometry by making it possible to obtain the mass spectra of nonvolatile, thermally unstable, and high-polarity compounds, which contain information on the molecular weight and the structure of the compounds studied. The mechanism of ion formation, the apparatus design, and also the main results of FAB mass spectrometric study of different classes of compounds are examined. This method is specially helpful in analysis of natural compounds.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 23, No. 1, pp. 62–78, January, 1987.     

Continuous-flow fast atom bombardment mass spectrometry

The continuous-flow fast atom bombardment probe performs equally well with or without a high-performance liquid chromatography column producing clean spectra containing little or no background noise. Its function as a liquid chromatography-mass spectrometry interface for labile and involatile samples has been illustrated with reference to dansylated amino acids. The versatility of the new probe has been exemplified by on-line enzymatic peptide sequencing.     

暗霉素的快原子轰击(FAB)质谱

快原子轰击(fast atom bombardment,简称 FAR)质谱是八十年代开发的质谱新技术.这种在室温条件下用具有一定能量的中性原子轰击样品进行离子化的技术特别适用予热稳定性差、难挥发、强极性样品的分析.我们用 FAB 对七个暗霉素(nebramycin)抗生素组分进行结构测定,获得了较满意的结果.暗霉素属氨基糖苷类抗生素.我们从我国土壤中分离的菌株发酵液中提取暗霉素复合物及其水解产物,并分离和鉴定了七个单一组分.这七个化合物(1～7)的结构如下: