FAB mass spectrometry

The luciferin produces a blue oxidation product during its purification process. In the DEAE chromatography of luciferin, this blue compound is eluted before the fractions of luciferin. The fractions of the blue compound were combined and purified by HPLC on a column of Hamilton PRP-1 (7 x 300 mm) using methanol-water (8 2) containing 0.1% ammonium acetate. The purified blue compound showed absorption peaks at 234, 254, 315, 370, 410, 590 (shoulder) and 633 nm. High-resolution FAB mass spectrometry of this compound indicated a molecular formula of C l C Nai m/z 609.2672 (M - Na + 2H)+, and mlz 631.2524 (M + H)+]. These data, together with the HNMR spectral data, indicated the structure of the blue compound to be 8. 

Laali and Lattimer (1989 see also Laali, 1990) observed arenediazonium ion/crown ether complexes in the gas phase by field desorption (FD) and by fast atom bombardment (FAB) mass spectrometry. The FAB-MS spectrum of benzenediazonium ion/18-crown-6 shows a 1 1 complex. In the FD spectrum, apart from the 1 1 complex, a one-cation/two-crown complex is also detected. Dicyclo-hexano-24-crown-6 appears to complex readily in the gas phase, whereas in solution this crown ether is rather poor for complexation (see earlier in this section) the presence of one or three methyl groups in the 2- or 2,4,6-positions respectively has little effect on the gas-phase complexation. With 4-nitrobenzenediazonium ion, 18-crown-6 even forms a 1 3 complex. The authors assume charge-transfer complexes such as 11.13 for all these species. There is also evidence for hydride ion transfer from the crown host within the 1 1 complex, and for either the arenediazonium ion or the aryl cation formed from it under the reaction conditions in the gas phase in tandem mass spectrometry (Laali, 1990). 

Neutral gangliolipids from Thermoplasma acidophilum were separated by PTLC, and their tentative structures were characterized by the combination of GC, H-NMR, and FAB-mass spectrometries [91]. The lipophilic portion of the neutral glycolipid was composed of caldarchaeol (dibiphytanyl-diglycerol tetraether), and the sugar moieties of the glycolipids were composed of glucose. 

Hieda et al. determined theophylline, theobromine, and caffeine in human plasma and urine by gradient capillary HPLC with frit fast atom bombardment (FAB) mass spectrometry with 7-ethyl theophylline as the internal standard.64... 

They have also examined the formation of the ir-complex between the silacalixarenes and silver cation by FAB mass spectrometry. Similar 77-complex formation with silver cation was observed for hexasila [2,2,2]paracyclophanes 37 (41). 

Similarly, other cycloadducts of nitrile oxides with C6o were synthesized. The cycloadducts were characterized by 13C NMR spectroscopy and high-resolution fast atom bombardment (FAB) mass spectrometry. It should be mentioned that X-ray structure determination of the 3-(9-anthryl)-4,5-dihydroisoxazole derivative of C6o, with CS2 included in the crystals, was achieved at 173 K (255). Cycloaddition of fullerene C60 with the stable 2-(phenylsulfonyl)benzonitrile oxide was also studied (256). Fullerene formed with 2-PhSC>2C6H4CNO 1 1 and 1 2 adducts. The IR, NMR, and mass spectra of the adducts were examined. Di(isopropoxy)phosphorylformonitrile oxide gives mono- and diadducts with C60 (257). Structures of the adducts were studied using a combination of high performance liquid chromatography (HPLC), semiempirical PM3 calculations, and the dipole moments. 

FAB mass spectrometry and UV/Vis spectroscopy have been used to demonstrate the binding of the cations to the complexes, and CV studies have provided quantitative measures of the perturbations which result on cation binding. This behaviour is quite complex and readers are encouraged to consult the original papers. However, it does indicate that receptors [42] and [44] show most promise as sensors for alkali metal cations. 

The elimination of arenes is not limited to the radical cations of the carotenoids. Just as the neutral compounds themselves also tend to undergo (thermal) cyclization followed by arene loss, the protonated analogues, e.g. ion 82 generated by Cl or fast atom bombardment (FAB) mass spectrometry are prone to eliminate one or even two arene molecules as well (Scheme 26)270. 

Example Cesium iodide is frequently used for mass calibration in fast atom bombardment (FAB) mass spectrometry (Chap. 9) because it yields cluster ions of the general formula [Cs(CsI)n] in positive-ion and [I(CsI)J in negative-ion mode. For the [Cs(CsI)io] cluster ion, m/z 2730.9 is calculated instead of the correct value m/z 2731.00405 by using only one decimal place instead of the exact values Mi33Cs = 132.905447 and M1271 = 126.904468. T e error of 0.104 u is acceptable for LR work, but definitely not acceptable if accurate mass measurements have to be performed. 

Continuous-Flow FAB Mass Spectrometry Caprioli, R.M., editor John Wiley Sons Chichester, 1990. 

Mass spectrometry. (+)Fast atom bombardment (FAB) mass spectrometry was carried out with a JEOL JMS-SX/SX102A mass spectrometer. Dried samples were dissolved in methanol-water, mixed with (thio-) glycerol, and applied to a direct insertion probe. During the high resolution FAB-MS measurements, a resolving power of 10,000 (10% valley definition) was used. Cesium iodide, glycerol, or polyethylene oxide (MWav = 600) was used to calibrate the mass spectrometer. 

Ongena M, Jacques P, van Vyncht G, Charlier P, de Pauw E, Thonart P, Budzikiewicz H (1998) Structural Analysis of Two Pyoverdins by Electrospray and FAB Mass Spectrometry. J Mass Spectrom Soc Jpn 46 53... 

Bah M, Pereda-Miranda R (1996) Detailed FAB-Mass Spectrometry and High Resolution NMR Investigations of Tricolorins A-E, Individual Oligosaccharides from the Resins of Ipomoea tricolor (Convolvulaceae). Tetrahedron 52 13063... 

General. NMR spectra were obtained on a Bruker WM-250 instrument with tetramethylsilane (TMS) as internal standard. UV-visible spectra were taken on a Varian Cary 219. Fast-atom bombardment (FAB) mass spectrometry (MS) analysis were completed on a Vacuum Generators ZAB-2F double-focusing or a Varian MAT CH5 mass spectrometer equipped with an Ion Tech FAB Gun. Solvents for FAB matrix were made up of thioglycerol, dithiothreitol, and dithioerythretol (2 1 1) addition of 0.1M trifluoroacetic acid to the matrix facilitated the ionization of the porphyrins during FAB analysis.(13)... 

Plavsic, Srzic and Klasinc performed a detailed electron impact mass spectrometric investigation of alkyllithium compounds . They have concluded that MeLi, /-PrLi, 5-BuLi and r-BuLi consist of tetrameric clusters only, while n-PrLi, n-BuLi and i-BuLi form mixtures of tetramers and hexamers, in the gas phase. Fast atom bombardment (FAB) mass spectrometry was used by Abdul-Sada, Greenway and Seddon to show that the extent of aggregation of f-BuLi is tetrameric while n-BuLi is hexameric (Table 1). Nevertheless, for both alkyllithium compounds the ion corresponding to (RLi)Li+ is the most abundant in the spectrum, as also shown in other studies of alkyllithium vapor. 

FAB mass spectrometry of cluster-opened 3 and the isomeric mixture of n-butyl-amine adducts 4 revealed an unprecedented fragmentation behavior [12]. Whereas the usual exohedral adducts of Cjq exhibit typical characteristics, namely relatively... 

Diagnosis of medium chain acyl-CoA dehydrogenase deficiency by stable isotope dilution analysis of urinary acylglycines retrospective and prospective studies, and comparison of its accuracy to acylcamitine identification by FAB/mass spectrometry. 

Fast-atom-bombardment (FAB)-Mass spectrometry has been used for the pharmaceutical analysis of corticosteroids [182]. The FAB-mass spectra of 24 corticosteroids (such as cortisone, prednisolone, hydrocortisone, and betamethasone) in were recorded in glycerol and/or thioglyeerol. The... 

Munoz, A. et al.. Identification and structural assessment of alkaline-earth metal complexes with flavonols by FAB mass spectrometry, Russ. J. Gen. Chem., 74, 438, 2004. Translated from Zh. Obshch. Khim., 74, 482, 2004. 

FIGURE 2.5. Schematic for FAB mass spectrometry. The intense activity at the surface of the sample produces neutrals, sample ions, ions from the matrix, etc. Only the ions are accelerated toward the analyzer. 

The structures of vanicosides A (1) and B (2) and hydropiperoside (3) were established primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy techniques and fast atom bombardment (FAB) mass spectrometry (MS).22 The presence of two different types of phenylpropanoid esters in 1 and 2 was established first through the proton (4H) NMR spectra which showed resonances for two different aromatic substitution patterns in the spectrum of each compound. Integration of the aromatic region defined these as three symmetrically substituted phenyl rings, due to three p-coumaryl moieties, and one 1,3,4-trisubstituted phenyl ring, due to a feruloyl ester. The presence of a sucrose backbone was established by two series of coupled protons between 3.2 and 5.7 ppm in the HNMR spectra, particularly the characteristic C-l (anomeric) and C-3 proton doublets... 

Matsnbara, T. Hagashi, A. (1991) FAB/mass spectrometry of lipids. Prog. Lipid Res. 30, 301-322. 

---