Solid Samples Investigated

To make the study as broad as possible, we have investigated 13 materials including plastics, minerals and metals. We also chose very different material qualities, from almost ideally chemically homogeneous surfaces and technical raw materials to finished commercial products. With this selection we have covered a broad spectrum of possible scientific and industrial applications, where knowledge about the solid SFE is desired. 

The change in SFE after plasma treatment was also investigated for PDMS, PVC and PET. 

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Why Test Inks Cannot Tell the Whole Truth 425 Table 17.1 List of solid samples investigated. 

When subjected to a step function loading, solid samples respond in one of the characteristic response modes described in Chap. 2. Often it is desired to investigate materials response to structured loading or even to shear-pulse loading. Both of these loadings can be achieved with the use of an intervening disk of a solid material placed between the loading and the sample. 

Dent et al. [47] also investigated the V K-edge EXAFS for the dissolution of [EMIM][VOCl4] and [NEt4][V02Cl2] in basic [EMIM]C1/A1C13 and compared the data with those of solid samples. In both cases the dissolved and the solid samples showed similar EXAFS and no coordination of the chloroaluminate species to, for example, the vanadyl oxygen was found. 

The technique as we have described it works only for polar molecules, because only they can interact with microwave radiation. However, variations of these spectroscopic methods can be used to investigate nonpolar molecules, too. A major limitation of the technique is that only the spectra of simple molecules can be interpreted. For complex molecules, we use solid samples and x-ray diffraction techniques. 

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] ... 

The first linkage between a microscope and an IR spectrophotometer was reported in 1949 [15]. Today, every manufacturer of IR spectrophotometers offers an optical/IR microscope sampling accessory. The use of optical and IR microscopy is a natural course of action for any solid state investigation. Optical microscopy provides significant information about a sample, such as its crystalline or amorphous nature, particle morphology, and size. Interfacing the microscope to an IR spectrophotometer ultimately provides unequivocal identification of one particular crystallite. Hence, we have the tremendous benefit of IR microscopy for the identification of particulate contamination in bulk or formulated drug products. 

Table 2 Various Types of Pharmaceutical Samples Investigated by Solid State NMR Spectroscopy...

NMR spectra of solids, and thus soil, are obtained by what is called magic angle spinning. The spectra obtained have broader absorption features than NMR spectra of components in solution or liquids. Numerous NMR experiments such as 3H—13C heteronuclear chemical shift correlation (HETCOR), which identifies which hydrogen atoms are attached to which carbon atoms, can also be carried out on solid samples. A great deal of useful information about the structure of components in soil can thus be obtained from NMR investigations [5,6],... 

X-ray fluorescence spectrometry was the first non-destructive technique for analysing surfaces and produced some remarkable results. The Water Research Association, UK, has been investigating the application of X-ray fluorescence spectroscopy to solid samples. Some advantages of nondestructive methods are no risk of loss of elements during sample handling operations, the absence of contamination from reagents, etc. and the avoidance of capital outlay on expensive instruments and highly trained staff. 

Magnetic susceptibility of paramagnetic particles is used to determine the concentration of ion-radicals but yields no structural information. The method often demands solid samples of ion-radical salts. Many ion-radical salts are unstable in the solid state, and this requirement turns out to be a decisive limit. Fortunately, there are special ways to determine magnetic susceptibility of paramagnetic particles in solutions (Selwood 1958). However, instruments for such measurements are rarely used in chemical laboratories. Besides, special devices should be used to conduct investigations at different temperatures. 

Our principal/principle objective is to investigate the long-term effects of these pollutants. Our methods will include (1) extraction, (2) concentration and (3) purification of liquid and solid samples. In principal/principle, the liquid samples should be easier to extract. 

Investigations on solid samples have been reported for a rather large variety of compounds generally using phosphorus resonance but in some cases proton, fluorine, boron and even 23Na resonances (1969 217) and relaxation time measurements have been used. Phosphides, and especially simple or mixed paramagnetic phosphides, have often been... 

Usually measurements are carried out with liquids or solutions, however, in differential microcalorimetry2 solids are investigated. Furthermore, optically active polymers have been investigated by polarimetry in the solid state19-20. For gas chromatographic analysis, the sample must be volatile without decomposition. 

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