Mass spectrometry fast bombardment

Desorption ionization (DI). General term to encompass the various procedures (e.g., secondary ion mass spectrometry, fast-atom bombardment, californium fission fragment desorption, thermal desorption) in which ions are generated directly from a solid or liquid sample by energy input. Experimental conditions must be clearly stated. 

Over the years, a lot of desorption ionization techniques have been introduced to MS, such as plasma desorption, field desorption, laser desorption, secondary ion mass spectrometry, fast atom bombardment, matrix assisted laser desorption and desorption electrospray ionization. Most of them are actually no longer used. In the following paragraphs, both matrix assisted laser desorption (MALDI) and desorption electrospray ionization (DESI) will be discussed. 

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. 

A Potent Structure Proof Technique Mass Spectrometry (Fast Atom Bombardment)... 

Fast atom bombardment mass spectrometry. Fast atom bom-bardment/mass spectrometry (FAB/MS) analyses were performed on a VG ZAB-HF mass spectrometer equipped with an Ion Tech fast atom gun. Xenon gas was activated to 8 kv and 1.5 mA ion current for the fast atom generation. An accelerating voltage of 8 kV was applied to the FAB source. The mass spectrometer was scanned from 800 to 80 amu using an exponential down scan mode at 5 seconds per decade with a 1 second interscan time. The data were recorded with a PDP 11/24 computer and were processed with VG 11/250 software. 

E. DePauw, A. AgneUo, and F. Davva, Liquid matrices for liquid secondary ion mass spectrometry-fast atom bombardment [LSIMS-FAB] an update. Mass Spectrom. Rev.lO, 283-301 (1991). 

Pauw, E.D., Agnello, A., Derw, F. (1991) Liquid Matrices for Liquid Secondary Ion Mass Spectrometry-Fast Atom Bombardment an Update. Mass Spectrom. Rev. 10 283-301. 

Facino RM, Sparatore A, Carini M, Gioia B, Arlandini E, Franzoi L (1991) Field desorption mass spectrometry, fast atom bombardment mass spectrometry and fast atom bombardment tandem mass spectrometry of echinacoside, the main caffeoyl-glycoside from Echinacea angustifolia roots (Asteraceae). Org Mass Spectrom 26 951-955... 

See also Chemical Ionization in Mass Spectrometry Fast Atom Bombardment Ionization in Mass Spectrometry Fragmentation in Mass Spectrometry Ion Structures in Mass Spectrometry Ion Trap Mass Spectrometers Ionization Theory Ion Energetics in Mass Spectrometry Ion Collision Theory Metastable Ions Quadrupoles, Use of in Mass Spectrometry Sector Mass Spectrometers Statistical Theory of Mass Spectra Time of Flight Mass Spectrometers. 

Fast-Atom Bombardment (FAB) and Liquid-Phase Secondary Ion Mass Spectrometry (LSIMS) Ionization... 

A big step forward came with the discovery that bombardment of a liquid target surface by abeam of fast atoms caused continuous desorption of ions that were characteristic of the liquid. Where this liquid consisted of a sample substance dissolved in a solvent of low volatility (a matrix), both positive and negative molecular or quasi-molecular ions characteristic of the sample were produced. The process quickly became known by the acronym FAB (fast-atom bombardment) and for its then-fabulous results on substances that had hitherto proved intractable. Later, it was found that a primary incident beam of fast ions could be used instead, and a more generally descriptive term, LSIMS (liquid secondary ion mass spectrometry) has come into use. However, note that purists still regard and refer to both FAB and LSIMS as simply facets of the original SIMS. In practice, any of the acronyms can be used, but FAB and LSIMS are more descriptive when referring to the primary atom or ion beam. 

The basic principles of fast-atom bombardment (FAB) and liquid-phase secondary ion mass spectrometry (LSIMS) are discussed only briefly here because a fuller description appears in Chapter 4. This chapter focuses on the use of FAB/LSIMS as part of an interface between a liquid chromatograph (LC) and a mass spectrometer (MS), although some theory is presented. 

FAB has evolved, and fast atoms are being replaced by fast ions, such as cesium (Cs+). This variation is called liquid secondary ion mass spectrometry (LSIMS) because the sample solution affords the secondary ion beam while the bombarding ions constitute the primary beam. Spectra... 

The term liquid secondary ion mass spectrometry (LSIMS) is sometimes used synonymously with FAB and is preferred by some as being more descriptive, since FAB could apply to bombardment of solid or liquid surfaces and does not indicate the types of secondaries investigated. In practice, little confusion is likely to result from using either term. Strictly, LSIMS can refer to the use of fast ions (FIB). 

Caprioli, R.M., Continuous-Flow Fast Atom Bombardment Mass Spectrometry, Wiley, New York, 1990. 

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