Fast-atom bombardment high-resolution mass spectrometry

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

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... 

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>. 

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. 

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. 

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. 

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. 

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. 

This is another field in which the uninitiated can be overwhelmed by acronyms, so some of the most widely used ones are explained here HRMS = high-resolution mass spectrometry HRGC/HRMS = high-resolution gas chromatography/HRMS LC/MS - liquid chromatography/mass spectrometry Cl = chemical ionization FD = field desorption FAB = fast atom bombardment LDMS = laser desorption mass spectrometry. 

Other Techniques. A growing technique related to lc/ms and regarded as complementary to it is that of capillary zone electrophoresis/mass spectrometry (cze/ms) (22). Using cze/ms, high resolution separation of water-soluble compounds is accompHshed by the principles of electrophoresis (qv). The sample is then coupled to the mass spectrometer by electrospray ionization (23) or a fast atom bombardment interface (fab) to produce molecular ions (24). Biotechnology applications of cze/ms have great potential (25). 

In most cases, the molecular ions of lupin alkaloids are detectable in electron impact (El) ionization technique, and, therefore, useful for determination of molecular mass and composition by the combination with high resolution mass spectrometry. However, N-oxides usually exhibit very small molecular ion peaks in the El mode. Inbeam ionization technique provides relatively strong molecular ions of the alkaloid N-oxides. However, fast atom bombardment (FAB) mass spectrometry has been recently proved very useful for the determination of the molecular masses of N-oxides. 

Kostiainen R, Matsuura K, Nojima K. Identification of trichothecenes by frit-fast atom bombardment liquid chromatography-high-resolution mass spectrometry. J Chromatogr. 1991 538(12) 323-330. 

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