LSIMS liquid secondary ion mass

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. 

Mass spectra were obtained with the following conditions ES (Electrospray) on anLCTOF MICROIVIASS El (Electronic Impact) and D/CI (Desorption/Chemical Ionization ammonia) on a SSQ7000 FINNIGAN LSIMS (Liquid Secondary Ion Mass Spectrometry) with a SCIEX PERKIN ELMER (Cs 35 KeV 3-nitrobenzyl alcohol matrix). 

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... 

Historically, the term SIMS was developed for bombardment of solid surfaces with ions, so, for greater descriptive precision, the name liquid secondary ion mass spectrometry (LSIMS) is better and can be used synonymously with FAB,... 

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). 

Mass Spectrometry. Mass spectrometry holds great promise for low-level toxin detection. Previous studies employed electron impact (El), desorption chemical ionization (DCI), fast atom bombardment (FAB), and cesium ion liquid secondary ion mass spectrometry (LSIMS) to generate positive or negative ion mass spectra (15-17, 21-23). Firm detection limits have yet to be reported for the brevetoxins. Preliminary results from our laboratory demonstrated that levels as low as 500 ng PbTx-2 or PbTx-3 were detected by using ammonia DCI and scans of 500-1000 amu (unpublished data). We expect significant improvement by manipulation of the DCI conditions and selected monitoring of the molecular ion or the ammonia adduction. 

Fast atom bombardment (FAB) Plasma desorption (PD) Liquid secondary-ion mass spectrometry (LSIMS) Thermospray (TSP)/plasmaspray (PSP) Electrohydrodynamic ionisation (EHI) Multiphoton ionisation (MPI) Atmospheric pressure chemical ionisation (APCI) Electrospray ionisation (ESI) Ion spray (ISP) Matrix-assisted laser desorption/ionisation (MALDI) Atmospheric pressure photoionisation (APPI) Triple quadrupole (QQQ) Four sector (EBEB) Hybrid (EBQQ) Hybrid (EB-ToF, Q-ToF) Tandem ToF-ToF Photomultiplier... 

Fast-atom bombardment (FAB) and liquid secondary-ion mass spectrometry (LSIMS) methods make up the category of the particle bombardment ionization. In both methods the analyte is dissolved in a liquid such as glycerol, thioglycerol, m-nitrobenzyl alcohol, or diethanolamine and about 1 1 is placed on a... 

In FAB, the sample is usually dispersed in a non-volatile liquid matrix, such as glycerol or diethanolamine, and deposited at the end of a sample probe that can be inserted into the ion source. The sample on the probe is ionised when bombarded by the fast atom beam. However, ionisation of the matrix also occurs, leading to a very large background signal. The technique is thus limited for the analysis of small molecules. Fast-moving ions (Cs+ or Ar+) can be used instead of fast-moving atoms, which is the basis of a technique called liquid secondary ion mass spectrometry (LSIMS). 

FAST ATOM BOMBARDMENT (FAB), LIQUID SECONDARY ION MASS SPECTROMETRY (LSIMS), AND CONTINUOUS-FLOW FAB OF CHLOROPHYLLS... 

Mass spectrometer or tandem mass spectrometer (JEOL, Micromass, MAT from ThermoFinnigan) equipped with direct insertion probe and fast atom bombardment (FAB) or liquid secondary ion mass spectrometry (LSIMS) for LC/MS or flow injection using continuous-flow FAB, mass spectrometer must be equipped with continuous-flow ionization source... 

Modern techniques of mass spectrometry allow the determination of some polymer characteristics. The main studies are devoted to mass determinations (no standardization necessary) of polyethyleneglycols, polystyrenes and polymethylmethacrylates. However, a liquid secondary ion mass spectrometry (LSIMS) study [42] on a thermal polymer of a mononadimide model compound permits an approach to the determination of the polymer microstructure and goes some way to understanding the polymerization mechanism. 

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