Silver compounds methods

Siloxane compounds, in vitreous silica manufacture, 22 414 Siloxane materials, 20 240 Siloxane oligomers, in silicone polymerization, 22 555-556 Siloxanols, silylation and, 22 703 Silsesquioxane hybrids, 13 549 Silsesquioxanes, 15 188, 22 589-590 SilvaGas process, 3 696, 697 Silver (Ag), 22 636-667. See also Silver compounds. See Ag entries Argentothiosulfate complexes Batch desilverizing Lead-silver alloys Palladium-silver alloy membranes analytical methods for, 22 650-651 applications of, 22 636-637, 657-662 as bactericide, 22 656, 657, 660 barium alloys with, 3 344 in bimetallic monetary system, 22 647-648 in cast dental gold alloys, 8 307t coke formation on, 5 266 colloidal precipitation color, 7 343t colloidal suspensions, 7 275 color, 7 334, 335... 

The separation and estimation of the two main groups of amino acids can be carried out in one experiment, instead of separately as described. The protein is hydrolysed by sulphuric acid, the tyrosine, cystine and diaminotrioxydodecanic acid are removed by crystallisation, and the diamino acids are precipitated by phosphotungstic acid. From this precipitate they are obtained by decomposition with baryta, and they are then separated by means of their silver compounds by Kossel, Kustcher and Patten s method. The filtrate from the phosphotungstic acid precipitate is freed from the excess of phosphotungstic acid by means of baryta, and the solution is treated by Fischer s ester method for the monoamino acids. 

Merry and Zarcinas [33] have described a silver diethyldithiocarbamate method for the determination of arsenic and antimony in soil. The method involves the addition of sodium tetrahydroborate to an acid-digested sample which has been treated with hydroxylammonium chloride to prevent the formation of insoluble antimony compounds. The generated arsine and stib-ine react with a solution of silver diethyldithiocarbamate in pyridine in a gas washtube. Absorbance is measured twice at wavelengths of 600 and 504 nm. 

The experimental techniques and theoretical interpretations of PES data have been discussed in detail in numerous articles and books. Some detailed reviews were published recently in this series1. Other reviews are too numerous to list so we shall mention only some of the more recent ones2-4. Our aim is not to give a detailed coverage of PES, but rather to provide a summary of PES methods which were used in studies of the electronic structure of gold and silver compounds. What all PES methods have in common is the basic phenomenon of photoionization, in which a photon of known energy hv becomes absorbed by the material and induces subsequent ejection of an electron (photoionization). The law of conservation of energy applied to the process can be expressed by equations 1 and 2,... 

As the cofacial dimer 1 is a readily available compound, the best method for the preparation of thiatriazinium salts is to treat 1 with nitrosyl tetrafluoroborate or hexafluorophosphate. The reaction mixture must be kept under inert gas during the evolution of nitrogen oxide. A direct method is the reaction of 1-fluorothiatriazines, e.g. 3, with arsenic(V) fluoride or phosphorus pentafluoride. The so-called silver salt method consists of the reaction of 1-chlorothia-triazincs with silver(I) hexafluoroarsenate in liquid sulfur dioxide. 

DISPOSAL AND STORAGE METHODS solid acid may be packaged and burned in incinerator . dissolve in flammable solvent and bum in incinerator equipped with effluent gas cleaning device store in a cool, dry location with adequate ventilation separate from strong oxidizers, strong alkalies, silver compounds and chlorites.. 

DISPOSAL AND STORAGE METHODS silver metal and soluble silver compounds may be disposed of in sealed containers in a secured, sanitary landfill, metallic silver may be routed to a metal salvage facility store in a cool, dry location maintain adequate ventilation keep in the dark, as most silver salts are light-sensitive separate from combustibles, such as acetylene, ammonia, hydrogen peroxide, and chlorine trifluoride. 

Monitoring of blood silver levels is the recommended method to determine the level of exposure, and levels below <25 pg/1 are not thought to lead to argyria. The ACGIH TLV is 0.01 m m for soluble silver compounds and 0.1 mg/m for silver metal. 

A variation of the typical anodized aluminum is Photosensitive Anodized Aluminum. This method uses the porous nature of unsealed anodized aluminum to create a sub-surface image. For this special case, the anodized aluminum is impregnated with a silver compound that creates an activated latent image when exposed to a source of light. After the developing and fixing processes take place... 

Ion-exchange. Ion-exchange reaction is regarded as a common method to prepare the silicate photocatalysts, typical for silver compounds AgaSiOj and Ag9(Si04)2N03. ... 

Silver ion titrations are nice because AgN03 is a primary standard. After drying at 110°C for 1 h to remove moisture, the solid has the exact composition AgN03. Methods for finding the end point in silver titrations are described in Section 6-6. Silver compounds and solutions should be stored in the dark to prevent photodecomposition and should never be exposed to direct sunlight. 

Theophylline behaves analytically like theobromine. It can be quantitatively methylated to caffeine by the method of Self and Rankin given above and it forms an insoluble silver compound. However, sodium acetate is sometimes present and will interfere with the silver determination unless the acetic acid is volatilised with excess of standard sulphuric acid. 

Precipitation of theophylline as the silver compound, which is filtered off, is a useful method particularly for tablet formulations ... 

The silver-containing wound dressings currently available have considerable differences in their overall structures, the concentration and formulation of the silver compounds, and the base materials used to carry the silver compounds. Many methods have been developed to incorporate silver into wound dressings. In general, these methods can be classified into the following four types. 

Carius method A method in quantitative analysis for determining the amounts of halogens, phosphorus, and sulfur in organic compounds. The compound is heated with concentrated nitric acid and silver nitrate in a sealed tube. The silver compounds produced are separated and weighed. 

---