Physical Microanalysis

C. Mazieres, Differential thermal microanAlysis, physical chemical applications. Bull. Soc. Chim. France 1961, 1695-1701. 

The powders of zeolites of various trademarks are used to produce petroleum-refining catalysts. In this connection, it is very important to have complete information concerning not only chemical composition and distribution of impurity elements, but also shape, surface, stmcture and sizes of particles. It allows a more detailed analysis of the physical-chemical characteristics of catalysts, affecting their activity at different stages of technological process. One prospective for solving these tasks is X-ray microanalysis with an electron probe (EPMA). 

L. Reimer. Transmission Electron Microscopy Physics of Image Formation and Microanalysis. Springer-Verlag, Berlin, 1984. This is an advanced but comprehensive source on TEM. Reimer also authored a companion volume on SEM. 

The correlation of phosphate precipitation with decrease of conductivity (Wilson Kent, 1968), increase in pH (Kent Wilson, 1969) and hardness (Wilson et al, 1972) is shown in Figure 6.16. These results demonstrate the relationship between the development of physical properties and the underlying chemical changes, but there are no sharp changes at the gel point. Evidence from infrared spectroscopy (Wilson Mesley, 1968) and electron probe microanalysis (Kent, Fletcher Wilson, 1970 Wilson et al, 1972) indicates that the main reaction product is an amorphous aluminophosphate. Also formed in the matrix were fluorite (CaF ) and sodium acid phosphates. 

Microanalysis is the common name used to refer to a variety of techniques for identifying, characterizing, and evaluating minute amounts of materials. Some microanalytical techniques are scaled-down versions of well-known conventional or physical analytical techniques others are specialized techniques that can be implemented only on extremely small samples. Table 11 lists the minimum size of samples required for microanalysis and the minimum amount of substance detectable by microanalytical techniques (Janssens and Van Grieken 2004). 

A number of procedures, based on microanalysis of samples for known physical properties (Chapter 8, 9, and 10), have also been employed. Eor example, field screening, which uses infrared spectroscopy, employing a portable version of the laboratory procedure has been used (Kasper et al., 1991). Eield turbido-metric methods favor the determination of high-boiling hydrocarbons and are... 

R. Ludwig, Transmission electron microscopy physics of image formation and microanalysis (3rd ed.). Springer, Berhn (1993). 

The coating chamber was equipped with a set of independently controlled stainless steel boats and a shutter system to enable the fabrication of multilayer structures. Pure selenium pellets were loaded into one boat and As Sei alloys into another. The two sources were evaporated sequentially (without breaking the vacuum) at boat temperatures of about 450 K. Typical coating rates were l j,m/min. After evaporation, they were allowed to anneal over several weeks in the dark at room temperature. During this period, due to structural bulk relaxation, most physical properties of the photoconductor film become stabilized. The compositions of the deposited films were determined by electron probe microanalysis, and the compositions quoted (0 < X < 0.20) are accurate to within 0.5 at.%. By shuttering the beginning and the end of the evaporation, a uniform arsenic composition across the film thickness can be obtained. In all experiments, a transparent gold electrode ( 300 jm thick) was used as the top contact. 

Reiiner, L.. cl a]. Scanning Electron Microscopy Physics of image Formation and Microanalysis. Springer-Verlag. Inc.. New York, NY, 199 . 

The Laser Raman microprobe constitutes a physical method of microanalysis based on the vibration spectra characteristic of polyatomic structures. A focused laser beam excites the sample. The light diffused by the Raman effect is used for identification and localisation of the molecular constituents present in the sample. An optical microscope allows a survey of the interesting structures and the placing of the laser beam. The spectra obtained from fossil organic particles generally match well the corresponding IR-spectra, but the features in particular yield additional information, which will be discussed below with the given examples (Fig. 23, p. 36). 

A Xany insights into early civilizations have been provided by the study of ceramics. Various physical and chemical methods are considered standard techniques for modem archaeology (I, 2). The macroanalysis, microanalysis, and trace chemical analysis of artifacts have added greatly to the understanding of prehistoric civilizations (3-6). The chemical techniques used for ceramic analysis have included spark source mass spectrometry (7) ... 

The Brownian motion of microdroplets is vigorous in solution. The volume of a micrometre-sized droplet is 10 - 10 dm. Therefore, a manipulation technique is indispensable for single microdroplet measurements. For the microanalysis of a single microdroplet, size of the probe should be smaller than that of the microdroplet. A light beam and a microelectrode are frequently used as a probe, and the analyses of small domains are performed by absorption/fluorescence microspectroscopy [24—29] and mi-croelectrochemical methods [17,30-32], In this section, single microdroplet techniques for the kinetic analysis of physical and chemical processes across a microdroplet/solution interface are described. 

To our knowledge, there are no detailed studies of the physical properties of the aqueous regions of SC intercellular spaces, and these indeed would be difficult to carry out. However, there is evidence in the literature that bears on this question. It is well established that the surface pH of skin in humans is less than 6 (Treffel et al., 1994). This suggests that a neutral pH is unlikely to occur in SC, and one in the range 5-6 is more probable. Similarly, Elias and co-workers have demonstrated the presence of calcium ions in SC intercellular spaces (Lee et al., 1992) others (Lindberg et al., 1992 Warner et al 1988) have shown by x-ray microanalysis that there is a relatively high ion concentration within the stratum comeum. 

The fiiU set of routine physical data which could and, ideally, should be obtained on a pure compound is as follows ir, uv, high field nmr ( H and l C), and low and high resolution mass spectra, m.p. or b.p., microanalysis (for a new compound). If the compound is optically active then the optical rotation must be measured. Only mass spectroscopy and microanalysis from this list are destructive techniques, but modem techniques mean that... 

There are several schools of thought on this topic. Some maintain that all new compounds must be analysed, whereas others say that, with the modem array of physical methods (high resolution nmr spectroscopy and high resolution soft ionization mass spectroscopy, for example) the need for combustion analysis no longer exists. Many follow a middle course and use microanalysis for crystalline compounds which are available in sufficient quantity, and high resolution mass spectrometric measurements in all other cases. The course you take will depend upon circumstances (the requirements of your supervisor or the department, for example). 

It was in 1949, at the first European conference on electron microscopy in DelO. that R. Castaing described the electron probe microanalyser he had designed under the guidance of A. Guinier. In his thesis (1951), Castaing also described the basic physical principles that were subsequently to make the microprobe a tool for quantitative microanalysis. Current electron microprobe analysers differ little in their basic principle from that originally described by Castaing. Of course, improvements have been made over the years, notably the enhancement of detection systems and the automation of the equipment. 

A striking feature of the cellular effects of bismuth compounds in animals (and one shared only by lead) is the production of intranuclear inclusion bodies of up to 5 ixm in diameter (87), for example, in the tubular epithelial cells of the kidney. Electron probe microanalysis shows that these contain both Bi and S, and so could be a complex with a Cys-rich protein such as metallothionein. Bismuth is known to be a potent inducer of renal metallothionein synthesis, and pretreatment of animals with bismuth salts can prevent some of the toxic side effects induced by cisplatin (88). The role of metallothionein in the pharmacology of bismuth remains to be established, but the strong involvement of zinc, also an inducer of metallothionein synthesis, in the metabolism of skin cells, for example, may be related. Like several other elements of Group V, the development of the biological chemistiy of Bi is hampered by the lack of good physical properties, in particular of a well-behaved NMR isotope. 

CyD ICs of diazirine 63 were prepared to determine the effect of supramolecular inclusion upon carbene 64. The a-CyD and /(-CyD ICs were analyzed using 111 NMR,14 including 2-D ROESY 15 ICD 17 and microanalysis. The integral structures of the CyD ICs were concluded to be 63 (a-CyD)2 and (63 / -CyD)2, based on their physical and chemical characteristics (vide infra). These stoichiometries denote that diazirine 63 is sandwiched between two a-CyD units, but that it forms a twofold 1 1 complex with /1-CyD.18 It has been demonstrated that a guest must have a substituent capable of hydrogen bonding, like —F or —OH,15,18 to effect an opposite inclusion orientation within CyD in the aqueous versus solid phase. Hence, it is likely that hydrophobic diazirine 63 adopted the same orientation within its CyD host during photolyses in both phases that were employed. 

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