Versus chemical analysis

Thomas, W. A. 1968. Calcium distribution in leaves Autoradiography versus chemical analysis. Int. J. Appl. Radiat. Isot. 19(6) 544-545. 

NiOi + y could be measured precisely by use of the solid electrolyte, without chemical analysis. This result is shown in Fig. 1.51, as log Po. versus T curves, in which the dotted lines indicate the iso-y values. This figure shows that in order to get stoichiometric NiO, the sample has to be prepared at low temperature and low oxygen partial pressure in the NiO phase region. 

Table 6.2 Copolymer composition Xt versus monomer feed composition x° of bulk radical copolymerization of glycidyl methacrylate M, and styrene M2 (T = 60 °C, p < 0.1). In three columns the experimental data obtained [217] by means of chemical analysis of epoxy group content (EA), Infra Red (IR) and Proton Nuclear Magnetic Resonance (NMR) spectra are presented...

Inks and prints are analysed in order to ensure safety. This includes testing for harmful substances with potential to migrate into food. Environmental pressure may result in a demand for testing, for example, vegetable oils versus petroleum distillates. There might also be a need to determine the content of aromatic compounds in the ink in order to avoid odour and taint problems. For chemical analysis of prints and determination of ink components a number of methods are available, such as pyrolysis, infra-red spectrometry, gas chromatography and mass spectrometry. Volatile compounds are usually analysed by a headspace technique. The progress in chemical analysis is so rapid that any method may be considered obsolete after a limited number of... 

Brandi, M., Meyer, M., and Suhnel, J. (2001) Quantum-chemical analysis of C-H- - -O and C H- - -N interaidions in RNA base pairs—H-bond versus anti-H-bond pattern, J. Biomol Struct. Dyn. 18, 545-555. 

Loss or gain versus time under specifically defined conditions (and by chemical analysis). 

Most Auger spectroscopy studies of surfaces are carried out for qualitative as well as quantitative surface chemical analysis [39]. Typical Auger spectra from alloy surfaces are shown in Figure 5.17. While the raw experimental data yield the electron intensity as a function of its energy (/ versus eV), it is usually displayed as the second derivative of intensity d I/dV as a function of electron energy eV. In this way the Auger peaks are readily separated from the background, due to other electron-loss processes that take place simultaneously. 

In the earliest studies of solid-state reactions between ceramic oxides, the width of the reaction product produced by bulk diffusion couples was determined by VLM. Using an SEM with a field-emission gun a much more precise EDS profile analysis can be performed providing chemical analysis at a spatial resolution of 2nm. Figure 10.33 shows a typical XEDS spectrum a plot of counts versus X-ray energy. The X-rays are produced as a result of electron transitions within the atoms in the sample. The transitions and, hence, the peaks are characteristic of specific atoms. A doped silicon crystal is used to detect the X-rays, where they cause the formation of electron-hole pairs. New methods for detecting the X-rays are being developed that use the change in temperature caused by the X-ray and are known as colorimeters. 

FIGURE 11-1. Theoretical working curve for fluorescence intensity versus atom concentration. [From J. D. Winefordner and T. J. Vickers, Atomic Fluorescence Spectrometry as a Means of Chemical Analysis, Anal. Chem., 36,161 (1964). Used by permission of the American Chemical Society.]... 

Potency analysis of the amorphous dispersion systems revealed that drug recovery was significantly higher with KinetiSol versus HME for comparable process feeds. In the case of Eudragit LlOO-55, the mean ROA potency value was 70.9 % for KinetiSol and 22.7 % for HME. The mean potency value for the HPMCAS-LF composition was 99.4 % with KinetiSol and 70.9 % for HME. A comparative summary of processing parameters and chemical analysis of the KinetiSol and HME products is provided in Table 18.1. The results demonstrated that KinetiSol was an effective method for producing ASDs where HME was not feasible, owing to the compound s thermal instability. 

X-ray photoelectron spectroscopy (XPS), also referred to as electron spectroscopy for chemical analysis, is a surface characterization technique based on the photoelectron effect. XPS surveys the electron binding energy spectrum of a sample surface resulting in a plot of binding energy versus total electron count. Since the binding energy of electrons of different elements is different, XPS can be used to identify the different elements present on the surface and the composition ratio of each element. In theory, XPS can detect all elements. However, H and He are barely detected in practical situations [46]. 

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