High resolution fast-atom-bombardment

HRFABMS High-resolution fast atom bombardment mass spectrometry... 

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. 

A novel pigment has been isolated from the petals of Rosa hybrida with complex chromatographic techniques and the structure was elucidated with spectroscopic methods and high resolution fast-atom bombardement mass spectrometry, lH NMR, and FTIR. Anthocyanins were extracted from 7.9 kg of petals of Rosa hybrida cv. M me Violet with 80 per cent aqueous ACN containing 0.1 per cent TFA. The extract was purified in a Sephadex LH-20 column, and the fraction eluted with 80 per cent ACN was further fractionated in a HP-20 column using water, 15, 20 and 30 per cent ACN as mobile phases. The last fraction was lyophilized and separated by preparative RP-HPLC using an ODS column (50 X 5 cm i.d.). Solvents were 0.5 per cent aqueous TFA (A) and water-methanol... 

Millington DS, Roe CR, Maltby DA (1984) Application of high resolution fast atom bombardment and constant B/E ratio linked scanning to the identification and analysis of acylcarnitines in metabolic disease. Biomed Mass Spectrom 11 236-241... 

The characteristic H(4)-H(5) H NMR coupling constants of the 3-oxabicyclo[3.2.0]heptane derivatives anti-% (V//,//=1.3 Hz) and ry -51 Jh,h = 5.6 Hz) have been used to establish the structural assignments for these isomers <20060L491>. The structure of the rearranged cembrane derivative ciereszkolide 52 has been elucidated by onedimensional (TD) and 2-D NMR spectra, high-resolution fast atom bombardment mass spectrometry (HRFAB-MS), infrared (IR), and ultraviolet (UV) as well as by single crystal X-ray analysis <2004EJ03909>. 

In off-line coupling of LC and MS for the analysis of surfactants in water samples, the suitability of desorption techniques such as Fast Atom Bombardment (FAB) and Desorption Chemical Ionisation was well established early on. In rapid succession, new interfaces like Atmospheric Pressure Chemical Ionisation (APCI) and Electrospray Ionisation (ESI) were applied successfully to solve a large number of analytical problems with these substance classes. In order to perform structure analysis on the metabolites and to improve sensitivity for the detection of the various surfactants and their metabolites in the environment, the use of various MS-MS techniques has also proven very useful, if not necessary, and in some cases even high-resolution MS is required. 

If high-resolution measurements are performed in order to assign elemental compositions, internal mass calibration is almost always required. The calibration compound can be introduced from a second inlet system or be mixed with the analyte before the analysis. Mixing calibration compounds with the analyte requires some operational skills in order not to suppress the analyte by the reference or vice versa. Therefore, a separate inlet to introduce the calibration compound is advantageous. This can be achieved by introducing volatile standards such as PFK from a reference inlet system in electron ionization, by use of a dual-target probe in fast atom bombardment, or by use of a second sprayer in electrospray ionization. 

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. 

Cai, Z.W., S.J. Monson, and R.F. Spalding (1996). Determination of atrazine and hydroxyatrazine in agricultural runoff waters by liquid chromatography and fast atom bombardment-high resolution mass spectrometry. J. Assoc. Off. Anal. Chem. Int., 79 929-935. 

In conclusion, I hope that I have shown that fast-atom bombardment mass spectrometry is a potentially useful tool for the synthetic chemist working in many areas of inorganic, organometallic, and coordination chemistry. In addition, as further fundamental research is done in the field with these applications in mind, the technique should become as routine as IR or NMR. Combined with developments in high-resolution NMR of solids, FAB should provide particularly useful data on supported catalytic reactions. Certainly FAB and the other complementary mass spectrometric techniques, mentioned in less detail, constitute a major way of quickly characterizing new compounds. 

Abbreviations m/z is the mass-to-charge ratio, M is the molecular weight of the molecule itself, M+ is the molecular ion, HRMS is high-resolution mass spectrometry, FAB is fast atom bombardment, and EIMS is electron-impact mass spectrometry. 

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. 

Hepatotoxins were isolated as new hepatotoxic compounds from the cyanobacterium Nostoc sp. strain 152 and assigned structures based on their high resolution FAB (fast atom bombardment) MS/MS, H and C NMR spectra, amino acid analysis and gas chromatography on a chiral capillary column by Namikoshi et al ... 

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