Chemical tests for

Detecting the presence of small, even invisible, amounts of blood is routine. Physical characteristics of dried stains give minimal information, however, as dried blood can take on many hues. Many of the chemical tests for the presence of blood rely on the catalytic peroxidase activity of heme (56,57). Minute quantities of blood catalyze oxidation reactions between colorless materials, eg, phenolphthalein, luco malachite green, luminol, etc, to colored or luminescent ones. The oxidant is typically hydrogen peroxide or sodium perborate (see Automated instrumentation,hematology). 

Chemical tests for particular types of impurities, e.g. for peroxides in aliphatic ethers (with acidified KI), or for water in solvents (quantitatively by the Karl Fischer method, see Fieser and Fieser, Reagents for Organic Synthesis J. Wiley Sons, NY, Vol 1 pp. 353, 528, 1967, Library of Congress Catalog Card No 66-27894). 

Caution is needed in applying the results of general chemical tests for glass durability across a wide spectrum of glass properties. Glass fibre strengths, for example, are sensitive to the physical, as well as the chemical, nature of the environment and should only be assessed by the direct strength measurements in conditions which closely approximate the final application situation . 

Fig. 19.15 Schematic representation of range of corrosion potentials expected from various chemical tests for sensitisation in relation to the anodic dissolution kinetics of the matrix (Fe-l8Cr-IONi stainless steel) and grain boundary alloy (assumed to be Fe-lOCr-lONi) owing to depletion of Cr by precipitation of Cr carbides of a sensitised steel in a hot reducing acid (after Cowan and Tedmon )...

There is no completely objective chemical test for rancidity. Rancidity is determined ultimately by taste and smell, and stability is determined ultimately by placing the food in storage and allowing it to become rancid. But numerous chemical tests can be applied by the experienced chemist as an aid to objectivity. 

The plastic bottle and dispensing tip is made of low-density polyethylene (LDPE) resin, which provides the necessary flexibility and inertness. Because these components are in contact with the product during its shelf life, they must be carefully chosen and tested for their suitability for ophthalmic use. In addition to stability studies on the product in the container over a range of normal and accelerated temperatures, the plastic resins must pass the USP biological and chemical tests for... 

Aren t Most Chemicals Tested for Safe Exposure Levels ... 

Md. The Edgewood tests were conducted over a 20-yr period ending in 1975, to learn how five major classes of chemicals tested for various military applications may affect humans. Some 6,720 soldiers took part In the programs, and 254 chemicals were administered by various routes. 

Fonreman, R, Mason, J.M., Valencia, R. Zimmering, S. (1994) Chemical mutagenesis testing in Drosophila. X. Results of 70 coded chemicals tested for the National Toxicology Program. Environ, mol. Mutag., 23, 208-227... 

Chemical tests for particular types of impurities, e.g. for peroxides in aliphatic ethers (with acidified KI), or... 

Chemical rockets 2 Cl77—Cl 78 Chemical sprays 2 Cl78 Chemical stabilizer 2 Cl78 Chemical tests for new explosives 2 C178 Chemical warfare (CW) 2 Cl78 Chemical wood pulp 2 C178... 

Soil chemists have rapid chemical tests for measurement of the amounts of plant-available K, P, and N, as well as other elements in soils which are essential to plants. When the quantity of an element is too low for efficient crop pioduction. it is added as feitilizer. such as KC1. Ca(H2P04)2, or ammonium or nitrate salts. Large chemical fertilizer industries are required for mining, refining, and preparation of chemical salts for soil application as fertilizers. 

Chemical Tests for New Explosives Title of NDRC, Div B report by R.McGill, OSRD 787(PBL No 30778X1942)... 

The addition reaction between bromine dissolved in an organic solvent, or water, and alkenes is used as a chemical test for the presence of a double bond between two carbon atoms. When a few drops of this bromine solution are shaken with the hydrocarbon, if it is an alkene, such as ethene, a reaction takes place in which bromine joins to the alkene double bond. This results in the bromine solution losing its red/brown colour. If an alkane, such as hexane, is shaken with a bromine solution of this type, no colour change takes place (Figure 14.13). This is because there are no double bonds between the carbon atoms of alkanes. 

Immediately upon connecting the cell to a source of direct current, a deposit of gray metallic zinc appears on the surface of the cathode and bubbles of chlorine gas appear at the surface of the anode. A simple chemical test for chlorine may be made by leading this gas into an aqueous sodium iodide solution, whereupon the solution assumes a yellow color caused by displacement of iodine by chlorine. Accordingly, it is concluded that the products of the electrolysis of a zinc chloride solution are elemental zinc and elemental chlorine, and the next problem is that of explaining the mechanism by which these products may be produced. 

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