Information Content of Quantitative Analysis

In contrast to qualitative tests, in quantitative analysis more than the two signal states shown in Fig. 9.1 (+/—) are evaluated. Depending on the un- 

The information content of quantitative analytical measurements is determined by three items  

Classical information theory according to Shannon [1948] and Bril-louin [1963] consider only items (1) and (2) the trueness of information has not been taken into account. 

In the case where no bias is relevant (x = xtrue)y Eq. (9.9) becomes 

The a priori distribution, which reflects our assumptions or preliminary information about the analyte in the sample, is frequently considered to be uniform, U(xmin, xmax) their probability density is given by 

---

Part—I has three chapters that exclusively deal with General Aspects of pharmaceutical analysis. Chapter 1 focuses on the pharmaceutical chemicals and their respective purity and management. Critical information with regard to description of the finished product, sampling procedures, bioavailability, identification tests, physical constants and miscellaneous characteristics, such as ash values, loss on drying, clarity and color of solution, specific tests, limit tests of metallic and non-metallic impurities, limits of moisture content, volatile and non-volatile matter and lastly residue on ignition have also been dealt with. Each section provides adequate procedural details supported by ample typical examples from the Official Compendia. Chapter 2 embraces the theory and technique of quantitative analysis with specific emphasis on volumetric analysis, volumetric apparatus, their specifications, standardization and utility. It also includes biomedical analytical chemistry, colorimetric assays, theory and assay of biochemicals, such as urea, bilirubin, cholesterol and enzymatic assays, such as alkaline phosphatase, lactate dehydrogenase, salient features of radioimmunoassay and automated methods of chemical analysis. Chapter 3 provides special emphasis on errors in pharmaceutical analysis and their statistical validation. The first aspect is related to errors in pharmaceutical analysis and embodies classification of errors, accuracy, precision and makes... 

Figure 5.1-1 Information contents of vibrational spectra. The number of intensity intervals and therefore the information which is available for quantitative analysis depends on the noise in the spectra.

The current excitement in powder diffraction is in quantitative analysis of the data. The book is laid out in a way that facilitates understanding the information content of the data, as well as best practices for collecting and analyzing data for quantitative analysis. After a very brief overview of the basic theory of diffraction from crystals and powders, data collection strategies are described, including X-ray, neutron and electron diffraction setups using modern-day apparatus including synchrotron sources. Data corrections that are essential... 

Quantitative determination is usually made gravimetrically, after extraction with dichloromethane or dioxane, whereby a separate extraction with petroleum ether is made to determine the quantity of extractable spinning oils. In this way the maximum fraction of extractable oligomers is determined, not the total oligomer content. The marked UV absorption at 250 nm also enables quantitative determination. More details of quantitative analysis can be found in the literature - - and further information, also on repairing faulty pieces, is available. ... 

Summaries of the information content of EPR spectroscopic methods (in particular on nitroxide radicals) and the length scales of interest are given in Fig. 3. Focusing on one radical ( observer spin ), the standard method continuous wave (CW) EPR at any temperature and echo-detected (ED) EPR at low temperatures give valuable information on the fingerprint of the radical. This is mainly the electronic but can also be the geometric structure of the radical center. From CW EPR spectral analysis and/or simulations, rotational motion on the time scale 10 ps - 1 ps can be characterized qualitatively and quantitatively. Furthermore, in CW EPR, radicals also intrinsically report on their immediate (usually up to a few solvation layers, maximum up to 2 nm) chemical environment (e.g., polarity, proticity, etc.). 

Numerous methods based on the correlation of other physical properties with protein content have been described. Some of them are so much less favorable than specific gravity or refractive index that they do not warrant extended discussion here. Others, such as electrophoresis (160, 161) and infrared absorption spectroscopy (162) are to be considered at this time as being primarily research methods until wider distribution of information and equipment is available. The interesting technique of spreading the protein on a liquid surface and measuring the area as a means of quantitative analysis was described by Hooft (163) and by Gorter and associates (164). The viscosity of formalin treated serum... 

The extraction of knowledge from spectroscopic data is of great interest since spectroscopic methods play a major role in structure identification and elucidation as well as in quantitative analysis. IR spectroscopy is a very useful method because of the high information content of an IR spectrum and its broad applicability. This is due to the speed of the method, both for the analysis itself and the time window that can be observed, and the simple techniques for sample preparation. 

In Total Reflection X-Ray Fluorescence Analysis (TXRF), the sutface of a solid specimen is exposed to an X-ray beam in grazing geometry. The angle of incidence is kept below the critical angle for total reflection, which is determined by the electron density in the specimen surface layer, and is on the order of mrad. With total reflection, only a few nm of the surface layer are penetrated by the X rays, and the surface is excited to emit characteristic X-ray fluorescence radiation. The energy spectrum recorded by the detector contains quantitative information about the elemental composition and, especially, the trace impurity content of the surface, e.g., semiconductor wafers. TXRF requires a specular surface of the specimen with regard to the primary X-ray light. 

Quantitative analysis of these images is accomplished in the same manner as for any microscope image, depending on the detail of analysis desired. Automated image analysis software can be used to provide a variety of information. Crystal phase volume (solid fat content UNIT D3.i) can be obtained by counting dark pixels (according to some empirical threshold factor). 

In addition to knowing the sequence of the amino-acid attachment, the total amino-acid content of a peptide or protein aids in the structural composition analysis. Total amino-acid composition gives information against which the sequence information can be referenced. Also the total amino-acid composition is an easier analysis to run routinely to verify protein-peptide composition. To do amino-acid analysis, the first step is to break the linkages between the amino acids in the protein (or the peptide) by hydrolysis of the bonds, often using hydrochloric acid at elevated temperatures. The resulting mixture of amino acids is then separated and quantitated using HPLC. 

While all pyrolysis oil production reactor systems produce similar materials, each reactor produces a unique compound slate. The first decision, especially for a potential chemical or fuel producer, rather than a reactor developer, is to determine what products to make and which reactor system to use. The operating parameters of any reactor system designed to produce pyrolysis oil, especially temperature, can be altered to change the pyrolysis oil product composition and yield. Different feedstocks will produce different pyrolysis oil compositions and by-products, e.g. amorphous silica from rice hulls or rice straw, fatty acids from pine. Finally, feedstock pretreatment and/or catalysis, or reactor-bed catalysis can be used to improve specific product yields (7). Reactor system developers need to examine what they can produce and make this information available to chemical manufacturers and suppliers/owners of biomass feedstocks. This assumes that analysis of die entire liquid product from thermal conversion can be made, including quantitative analysis for any compounds that are being considered for recoveiy. Physical characterization - pH, viscosity, solids content, etc.is also needed. However, what can be produced is of no value, if it cannot be recovered or used economically. This involves examining the trade-offs between yield and current commercial value, recovery costs, and potential commercial value,... 

---