Quantitative microanalysis

Quantitative Microanalysis with High Spatial Resolution. (G. W. Lorimer, M. H. Jacobs, and P. Doig, eds.) The Metals Society, London, 1981. Research papers giving results from many materials. 

Stoichiometric variations in compositions of a material and of surface layers can be revealed by AEM. Because a relatively small amount of scattering occurs through a thin HRTEM specimen, X-rays are generated from a volume that is considerably less than in the case of electron microprobe analysis (EPMA). For quantitative microanalysis, a ratio method for thin crystals (57) is used, given by the equation ... 

Daniel PF, De Feudis DF, Lott IT, McCluer RH (1981) Quantitative microanalysis of oligosaccharides by high performance liquid chromatography. Carbohydr Res 97 161-180 De Jong JG, Aerts JM, van Weely S, et al (1998) Oligosaccharide excretion in adult Gaucher disease. J Inherit Metab Dis 21 49-59... 

These are the basic equations of quantitative microanalysis and are easily extended to specimens containing more kinds of atoms. For a specimen containing three kinds of atoms A, B, and C, 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. 

Counting X-ray photons with a given energy level can be used to determine the mass concentration of the emitting element in the analysis volume being studied. The measurement of these intensities serves as a basis for quantitative microanalysis. 

Siiry, P. Quantitative microanalysis of copper and aluminium by paper-chromatography. 

Quantitative microanalysis is more difficult than fluorescence analysis of macroscopic samples, whichever method is used ... 

Owing to the low temperature requirement, this type of method has not been extensively used or investigated for quantitative microanalysis. It should be noted, however, that the albumin separation is satisfactory even when the temperature during filtration rises as high as 7°C (PIO). Careful control at temperatures below zero is demanded for the ethanol fractionation scheme of Cohn et al. (C14). The higher dielectric constant of methanol undoubtedly renders the earlier method less sensitive to small changes in the many variables—temperature, molarity, pH of buffer, concentration of solvent and serum— and less likely to be adversely affected by albumin denaturation. ... 

Quantitative microanalysis performed by STEM/EDX showed that the two metals are evenly distributed over graphite leaflets. Graphite as support does not modify the selectivities of the catalysts we prepared nickel chromium catalysts have to be chosen in order to obtain citronellal whereas nickel molybdenum catalysts have to be preferred for the production of citronellol. 

Phosphate accessory phases contain a wealth of petrologic and chronological information, but each possesses particular properties that make accurate quantitative microanalysis difficult. This chapter provides an overview of the literature concerned with the main problems of electron microprobe (BMP) phosphate analysis. These include the volatility of fluorine in F-bearing apatite, and the mutual interference of L- and M-line X-rays from the major and trace elements in monazite and xenotime, along with consideration of standards, detection limits, absorption edges, and ZAF corrections in REE phosphates. 

At that time, the techniques for quantitative microanalysis of organic fluorides were quite inadequate until an outstanding complexometric method was devised in Belcher s laboratory (13). It appeared from extensive surveys that fluorofatty acids in fact were widespread in trace quantities in many species of green plants. 

Results show that EVLS is a useful and sensitive tool not only for both qualitative and quantitative microanalysis of adenine by means of Cu(I) ions but also for revealing details in corresponding electrode processes. 

M.G. Burke, M. Watanabe, D.B. Williams and J.M. Hyde, Quantitative characterization of nanoprecipitates in irradiated low-alloy steels advances in the apphcation of FEG-STEM quantitative microanalysis to real materials , J. Mater. ScL, 2006,41,4512-4522. 

Lee, K-R., Suzuki, T., Kobashi, M., Hasegawa, K., and Iwai, K., 1976, Quantitative microanalysis of capsaicin, dihydrocapsaicin, and nordihydrocapsaicin using mass frag-mentography, y. Chromatogr. 123 119-128. 

Quantitative Microanalysis. in transmission nexafs spectroscopy, qnan-titative analysis can be achieved by inverting Lambert-Beer s law of x-ray absorption ... 

The electrons cannot produce the characteristic x-rays if they do not have sufficient energy. Thus the x-rays do not come from the whole interaction volume, but from the region where the electron has not lost too much energy. The size of this region will depend on the beam energy, the x-ray energy and the composition of the material. Problems of this sort make quantitative microanalysis difficult (see refs 23-26, 119-122 in Chapter 2). 

Egerton, R.F., 1984b, Quantitative microanalysis by electron energy-loss spectroscopy the current status, in Scanning Electron Microscopy II (AMF O Hare, Chicago) p. 505. 

Table 5.29 shows the main characteristics of EPMA. The EDS mode provides several inherent advantages relative to WDS (i) simultaneous spectral acquisition (minimising beam damage) (ii) allowance for quantitative microanalysis of rough surfaces or particles and (Hi) spectrum imaging [250]. It is waste of time to proceed with quantitative microanalysis from a XEDS spectrum without first carrying out qualitative analysis. This requires that every peak in a spectrum be identified unambiguously and with statistical certainty. 

More common is elemental analysis using the x-rays emitted from the specimen in the SEM [30,33,187,188] and the TEM [30,51,189,190], X-ray analysis is m< t useful for heavier elements, so in polymers it is often applied to find out the nature of fillers and contaminants or the location of heavy elements (such as the chlorine in polyvinyl chloride) in polymer blends. Quantitative microanalysis of heavier atoms dispersed within a single phase polymer may be more difficult. The technique is limited by the sensitivity of polymers to radiation and heat damage from the intense electron beam needed for microanalysis. 

Quantitative microanalysis is difficult in principle but largely automated for homogenous samples [38, 59, 69]. If the sample has layers of thickness comparable with the penetration depth, or particles of size comparable with the interaction volume, analysis can be difficult. 

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