Solids direct spectrometric analysis

Applications Specific applications of the direct spectrometric analysis methods of solid samples of Table 8.36 are given under the specific headings. One investigation that is practically only possible by direct solids analysis is checking the homogeneity of polymers [136,137] this is of significance for reference materials and for quality control. A method for the assessment of microhomogeneity should meet various requirements [223] ... 

Kehden A., Flock J., Vogel W. and Broekaert J. A. C. (2000) Direct solids atomic spectrometric analysis of metal samples by laser induced argon spark ablation coupled to ICP-OES, Appl Spectrosc, in press. 

Laser based mass spectrometric methods, such as laser ionization (LIMS) and laser ablation in combination with inductively coupled plasma mass spectrometry (LA-ICP-MS) are powerful analytical techniques for survey analysis of solid substances. To realize the analytical performances methods for the direct trace analysis of synthetic and natural crystals modification of a traditional analytical technique was necessary and suitable standard reference materials (SRM) were required. Recent developments allowed extending the range of analytical applications of LIMS and LA-ICP-MS will be presented and discussed. For example ... 

The introduction of inductively coupled plasma (ICP) in inorganic mass spectrometry means that there is an effective ion source operating at atmospheric pressure. Whereas solid mass spectrometric techniques allow direct analysis of solid samples in ICP-MS, the determination of trace impurities or isotope ratios in solid samples is often carried out after digestion and dissolution of the material. For the determination of trace impurities and isotope ratios in liquids, an additional nebulization... 

Other Observations The assumption that azides decompose with partial release of nitrogen in the form of free atoms is confirmed by L vov [47] by direct mass-spectrometric analysis of the primary decomposition products of NaNs. Analysis of the initial mass-spectrometric patterns reported by Walker [49], taking into account partial dissociation of N2 molecules in the ionizing chamber of a quadrupole mass spectrometer, and the differences in the ionization cross sections of N and N2 and in the solid angles of the inlet of these species into the ionizing chamber, showed that the ion current ratio /(N+)//(Nj) in Walker s experiments [49] was 0.86, which is consistent with the estimate based on thermochemical data (Table 16.21). 

A key difference between El and Cl on the one hand and FAB, LSIMS, and LD on the other is the fact that sampling in FAB and LSIMS is from a speciHed location that corresponds to the impact footprint of the primary particle beam. If the sample is a solution, as it often is for FAB and LSIMS mass spectra of discrete samples, then diffusion within the solution blurs the spatial resolution of the ionization method. If the sample is held in a solid state, a diffusion-controlled liquid state, or within a substrate such as a thin-layer chromatogram, the spatial resolution inherent to the sampling method is preserved. The natural compatibility of FAB, LSIMS, and LD with the direct mass spectrometric analysis of TLC plates is readily apparent. 

Engel U., Kehden A., Voces E. and Broekaert j. a. C. (1999) Direct solid atomic emission spectrometric analysis of metal samples by an argon microwave plasma torch coupled to spark ablation, Spectrochim. Acta, Part B 54 1279-1289. 

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