Inorganic constituents determination

In order to sieve samples that are to have their inorganic constituents determined, the soil is ground to pass through a nylon sieve meeting the requirements of BS 410i77. This avoids sample contamination associated with the use of metallic sieves. When sieving samples prior to the determination of organic constituents, a metal sieve may be used provided it does not react with the determinand of interest. 

It is customary in analytical chemistry to examine unknown samples by a screening procedure using a multicomponent method like OES or MS in case of inorganic constituents on the one hand and GC or HPLC in case of organic constituents on the other. In this way, an overview can be obtained on the type of constituents and their approximate contents. In many cases it is necessary to get a deeper insight into the sample composition. For this reason, the one or a few constituents have to determine more precisely. 

A majority of soil extractions of inorganic constituents are carried out to determine the metal content of a soil sample. In these cases, it is common to use add extracting solutions. Dilute hydrochloric and sulfuric acids are most commonly used. Nitric acid is an oxidizer, so undesired oxidation can occur during the extraction process using this reagent. Phosphate is a natural... 

The presence and concentration of various metallic elements in petroleum coke are major factors in the suitability of the coke for various uses. In the test method (ASTM D5056), a sample of petroleum coke is ashed (thermally decomposed to leave only the ash of the inorganic constituents) at 525°C (977°F). The ash is fused with lithium tetraborate or lithium metaborate. The melt is then dissolved in dilute hydrochloric acid and the resulting solution is analyzed by atomic absorption spectroscopy to determine the metals in the sample. However, spectral interferences may occur when using wavelengths other than those recommended for analysis or when using multielement hollow cathode lamps. 

Minerals. Determinations of inorganic constituents (e.g. total ash, alkalinity of the ash) are classical methods for estimating juice content of citrus juices and beverages. Refinements were made to correct for inorganic sulfites, benzoates and phosphates used as adulterants or preservatives (34). 

Ash, as determined by the standard test method (ASTM D-3174), is the residue remaining after burning the coal and coke and differs in composition from the original inorganic constituents present in the coal. Incineration causes an expulsion of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrites into ferric oxide, and other chemical reactions. In addition, the ash, as determined by this test method, will differ in amount from ash produced in furnace operations and other firing systems because incineration conditions influence the chemistry and amount of the ash. 

In view of the wide variety and concentrations of inorganic constituents in aquatic environments, there are a great number of analytical techniques used to determine these compounds. They include... 

A great number of different standard and nonstandard analytical methods are available for the determination of inorganic constituents in water. Since the concentrations of some inorganic constituents are relatively high in water, classical methods (gravimetry and titration) were mostly used in early experiments. These methods, however, have been largely replaced, chiefly by faster, more sensitive, and more sophisticated instrumental methods. 

Tables 12.3 through 12.8 summarize different standard or official methods for the determination of inorganic constituents. Table 12.3 shows the main procedures for nutrient determinations it can be seen that UV-VIS spectrophotometry50-52-5 60 and ISE50-53-54-56 are the most commonly used analytical techniques.

Other nonstandard methods (including CE and ASV) commonly used for determining inorganic constituents in water are summarized in selected monographs.114-117... 

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