Chemical analysis INDEX

Many attempts have been made to characterize the stabiUty of the colloidal state of asphalt at ordinary temperature on the basis of chemical analysis in generic groups. For example, a colloidal instabiUty index has been defined as the ratio of the sum of the amounts in asphaltenes and flocculants (saturated oils) to the sum of the amounts in peptizers (resins) and solvents (aromatic oils) (66) ... 

PART A FUNDAMENTALS OF QUANTITATIVE CHEMICAL ANALYSIS Contents - page 882 Index - page 855 Cover Page - 879 Back Page - 878... 

These nitridooxophosphates are stable in water and 1 N HC1, which is useful to extract eventual by-products. Their composition has been undoubtedly established by a complete chemical analysis. The XRD powder patterns can be indexed with hexagonal parameters (Z = 6) as illustrated for the potassium compounds ... 

ZSM-5 and ZSM-11 samples were prepared as previously described (11) using tetrapropy 1 ammonium hydroxide and tetrabutyl ammonium bromide, respectively. The nature and crystallinity of the materials were verified by X ray diffraction, ir spectroscopy of lattice vibrational bands ( 1 2 ), n-hexane adsorption capacity at room temperature and constraint index (13) measurements. All samples correspond to highly crystalline ZSM-5 or ZSM-11 materials. The chemical compositions of the samples as determined from chemical analysis of A1 and Na contents, are given in table 1. 

Some of the simplest techniques and instruments are valuable tools for chemical analysis. This chapter is designed to remind students that simple, rapid methods are advantageous in many situations. These methods are often used for quality control purposes. The methods discussed here are melting and boiling points, viscosity, density or specific gravity and refractive index. 

Analysis procedures can be additionally classified into procedures that involve physical properties, wet chemical analysis procedures, and instrumental chemical analysis procedures. Analysis using physical properties involves no chemical reactions and at times relatively simple devices (although possibly computerized) to facilitate the measurement. Physical properties are especially useful for identification, but may also be useful for quantitative analysis in cases where the value of a property, such as specific gravity or refractive index (Chapter 15), varies with the quantity of an analyte in a mixture. 

An important feature of the analytical methods for the total petroleum hydrocarbons is the use of an equivalent carbon number index (EC). This index represents equivalent boiling points for hydrocarbons and is the physical characteristic that is the basis for separating petroleum (and other) components in chemical analysis. 

Computing the index of Hazard on the base of chemical analysis and attribution to the class of hazard... 

For the unequivocal characterization of a low-molecular-weight compound, it is sufficient to specify a few physical or chemical properties, for example, boiling point, melting point, angle of optical rotation, refractive index, elemental analysis, IR and NMR spectra. If two low-molecular-weight samples have the same characteristic properties, they may be considered as identical. 

There arc several conventional tests required hy consumers of ground mica. They include screening and Ihe determination of bulk density, true specific gravity, chemical analysis, moisture, free silica, refraction index, oil absorption, brightness, grit content, and aspect ratio. 

Rev. ed. of CRC handbook of basic tables for chemical analysis, cl989 Includes bibliographical references and index. 

EMEP. 2001. Manual for Sampling and Chemical Analysis. Revised November 2001. Kjeller, Norway Norwegian Institute for Air Research. EMEP/CCC Report 1/95. URL http //www.nilu.no/projects/ccc/ manual/index.html. 

X-Ray Diffraction Data. The X-ray diffraction powder patterns of the cancrinites, referred to in the synthesis section, have been indexed in accordance with the space group P63 as found by Jarchow (16). Table II reports the cell parameters of the three synthetic cancrinite samples and of a natural sample (16) for comparison. Chemical Analysis. Data for the three cancrinite samples on anhydrous basis are shown in Table III. Values of water content are reported in the next section. 

Component-based approach. This is an option if the mixture composition can be determined, for example, by means of chemical analysis, and if a mixture model is available that can predict the mixture effects. The mixture model can either be simple, for example, summation of PEC/PNEC ratios over all compounds into a hazard index (HI) moderately complex, for... 

For analysis of the samples, a physical method is often preferable to chemical methods. Chemical analysis nsually is appropriate only when a simple titration of each sample is involved, as in the case of the system HCI-H2O. If a physical property is chosen as the basis for an analytical method, it should be one that changes significantly and smoothly over the entire composition range to be studied. The refractive index is one property that can be used for the cyclohexanone-tetrachloroethane system. The values of are 1.4507 for cyclohexanone and 1.4942 for 1,1, 2,2 -tetrachloroethane, and log is almost a linear... 

A successfid indexing of the powder diffraction pattern, which can often be done automatically, yields the unit cell dimensions and information on possible space groups. The chemical analysis and sorption data indicate the framework density, or number of tetrahedra per unit cell. The challenge is then to position these tetrahedra within the unit cell such that (1) they fully interconnect in a sensible manner and (2) the necessary analytical data are reproduced. These structural constraints are quantified in an energy expression and simulated annealing [33,34] is employed as the global optimization approach. 

A 43-year-old woman with rheumatoid arthritis developed dizziness having taken celecoxib 200 mg/day for 2 weeks. At the start of treatment she had normal renal function (104). Her serum creatinine was 670 pmol/l (7.4 mg/dl) and blood urea nitrogen 30 mmol/1 (90 mg/dl). Creatinine clearance was 16 ml/minute. Urinalysis was normal and casts were not present. Urinary chemical analysis showed a sodium concentration of 18 mmol/1, a fractional excretion of sodium of 0.3, and a renal failure index of 0.493, consistent with prerenal acute renal insufficiency. Celecoxib was withdrawn. Although her renal function then improved, her serum creatinine was still abnormal (4.7 mg/dl) 1 month later. 

Allen, J.W., Gartz, J. Guzman, G. (1992). Index to the botanical identification and chemical analysis of the known species of the hallucinogenic fungi. Integration, 2 3, 9197. Allen, J.W. Merlin, M.D. (1992). Psychoactive mushroom use in Koh Samui and Koh Pha-Ngan, Thailand. Journal of Ethnopharmacology, 35, 205228. 

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