Secondary mass spectrometry

Scorch query, database. 56 Sebairol. See Ruuimidc Secobarbital, metabolism of. 76.77.81 Secobaibilat sodium. 494t. 495 Seconal. See Secobarbital sodium Secondary mass spectrometry. 52 Second messengers. 171. 172. 552 Secretin. 854 Seciral. See Acebuiolol Sedatives. See Anxiolytics, hypnotics, and sedatives... 

Secondary mass spectrometry (SIMS), XPS and Auger spectroscopy are suitable to study the thick oxide films, as the nature and composition of them are strongly dependent on the electrode potential and the current distribution of the corrosion process. Thus, the local chemical composition can define the mass transport (metal ions, anions, water, etc.) effects to corrosion and then, the dissolution rate too. 

Electron microscopy is a common technique for determining the filler distribution in a heterogeneous elastomer blends. Dias and Galuska (1996) have used time of flight secondary mass spectrometry (TOF-SIMS) to simultaneously determine the morphology as well as curative diffusion in BIMS-diene elastomer blends. 

In Chapter 4, titled Principles of Mass Spectrometry Imaging Applicable to Thin-Layer Chromatography, the authors first introduce a budding analytical approach known as imaging mass spectrometry (IMS) strategy and then present some successful examples of its practical applications. Then, they introduce in detail three mass spectrometric techniques as those routinely used within the framework of IMS. These are secondary mass spectrometry (SIMS), matrix-assisted laser desorption/ ionization (MALDI-IMS), and desorption electrospray ionization (DESI). Finally, the authors discuss the advances and bottlenecks of these techniques when applied to TLC. 

Chapter 6, titled Selection of Ionization Methods of Analytes in the TLC-MS Techniques provides an overview of mass spectrometric techniques that can be coupled with TLC and act as specific detectors in this hyphenated approach. The mass spectrometric techniques discussed in this chapter are secondary mass spectrometry (SIMS), liquid secondary ion mass spectrometry (LSIMS), fast atom bombardment (FAB), matrix-assisted laser desorption/ionization (MALDI), atmospheric pressure matrix-assisted laser desorption/ionization (AP-MALDI), electrospray ionization (ESI), desorption electrospray ionization (DESI), electrospry-assisted laser desorption/ionization (ELDI), easy ambient sonic spray ionization (EASI), direct analysis in real time (DART), laser-induced acoustic desorption/electrospray ionization (LIAD/ESI), plasma-assisted multiwavelength laser desorption/ionization (PAMLDI), atmospheric-pressure chemical ionization (APCI), and dielectric barrier discharge ionization (DBDI). For the sake of illustration, the authors introduce practical examples of implementing TLC separations with detection carried out by means of individual mass spectrometric techniques for the systematically arranged compounds belonging to different chemical classes. 

Time-of-flight secondary mass spectrometry Ultraviolet... 

Ions are also used to initiate secondary ion mass spectrometry (SIMS) [ ], as described in section BI.25.3. In SIMS, the ions sputtered from the surface are measured with a mass spectrometer. SIMS provides an accurate measure of the surface composition with extremely good sensitivity. SIMS can be collected in the static mode in which the surface is only minimally disrupted, or in the dynamic mode in which material is removed so that the composition can be detemiined as a fiinction of depth below the surface. SIMS has also been used along with a shadow and blocking cone analysis as a probe of surface structure [70]. 

Benninghoven A, Rudenauer F G and Werner FI W 1987 Secondary ion Mass Spectrometry Basic Concepts, instrumentai Aspects, Appiications, and Trends (New York Wiley)... 

Chang C-C and Winograd N 1989 Shadow-cone-enhanced secondary-ion mass-spectrometry studies of Ag(110) Rhys. Rev. B 39 3467... 

Secondary ion mass spectrometry (SIMS) is by far the most sensitive surface teclmique, but also the most difficult one to quantify. SIMS is very popular in materials research for making concentration depth profiles and chemical maps of the surface. For a more extensive treatment of SIMS the reader is referred to [3] and [14. 15 and 16]. The principle of SIMS is conceptually simple When a surface is exposed to a beam of ions... 

Vickerman J C, Brown A and Reed N M (eds) 1989 Secondary Ion Mass Spectrometry, Principles and Applications (Oxford Clarendon)... 

Briggs D, Brown A and Vickerman J C 1989 Handbook of Static Secondary Ion Mass Spectrometry (Chichester Wiley)... 

Barish E L, Vitkavage D J and Mayer T M 1985 Sputtering of chlorinated silicon surfaces studied by secondary ion mass spectrometry and ion scattering spectroscopy J. AppL Phys. 57 1336-42... 

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. 

Modern commercial lasers can produce intense beams of monochromatic, coherent radiation. The whole of the UV/visible/IR spectral range is accessible by suitable choice of laser. In mass spectrometry, this light can be used to cause ablation, direct ionization, and indirect ionization (MALDI). Ablation (often together with a secondary ionization mode) and MALDI are particularly important for examining complex, intractable solids and large polar biomolecules, respectively. 

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... 

Confusingly, FAB is sometimes called secondary ion mass spectrometry (SIMS), the secondary referring to the nature of the process (primary bombardment, secondary emission), but see next item. 

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,... 

In the case of fast ions, the terminology of secondary ion emission mass spectrometry (SIMS) is more obvious in that a primary incident beam of ions onto a target releases secondary ions after impact. 

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). 

The three techniques — laser desorption ionization, laser ablation with secondary ionization, and matrix-assisted laser desorption — are all used for mass spectrometry of a wide variety of substances from rock, ceramics, and bone to proteins, peptides, and oligonucleotides. 

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. 

LSIMS. liquid-phase secondary ion mass spectrometry... 

SIM. selected (or single) ion monitoring SIMS, secondary ion mass spectrometry SIR. selected (or single) ion recording... 

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