Phosphorus-containing reagents determination

The reaction between ozone and arsine leads to an emission continuum in the visible region and a discrete emission in the UV. The hydrides of arsenic, antimony, and tin can be determined down to sub-ppb levels. The chemiluminescent reaction between ozone and phosphine has been employed to determine phosphate and other phosphorus-containing compounds after reduction. The chemiluminescent oxidation of silane was used to determine silicate in natural waters. A variety of applications involving ozone as a reagent gas have been included in Table 2. 

It has been proposed that the overall reaction for thionations by the P4S10/HMDO combination follows eq 10. This conclusion was reached by analysis of the amounts of reagents consumed under the limiting conditions of a large excess of HMDO, and by NMR determination of the nature and amounts of phosphorus-containing products. 

If a water sample contains both soluble and insoluble manganese (Mn) compounds and ions, and it is filtered to separate the dissolved and insoluble fractions, and the filtrate and insoluble residue are analyzed separately, the results can be expressed as total dissolved Mn and total suspended or insoluble Mn. Phosphorus (P) can be determined colorimet-rically as the ortho-phosphate ion, P043, in aqueous samples after a reaction that forms an intensely blue-colored derivative. However polyphosphate ions and other ions and compounds containing P do not form this derivative. Total P in a sample can be determined with the same colorimetric procedure after acid hydrolysis and oxidation of all ions and compounds containing P to P04 3. In some elemental analyses the sample is treated with reagents designed to make available for measurement some fraction of an element or elements but not the total amount. For example, a soil sample may be treated with water at pH 3 to simulate the leaching process of acid rain. A total elemental analysis of the filtrate provides information about just those elements solubilized by the mild acid treatment. This can be called the determination of total mild acid leachable elements. 

The PE 2400 CHN Analyzer (Fig. 4) can be modified to perform automatic determination of oxygen. The combustion tube is filled with platinized carbon reagent. The samples are pyrolyzed in an inert atmosphere of argon or helium. The reaction product CO is separated by frontal chromatography and measured by thermal conductivity. In the Leco CHN Analyzer, carbon monoxide is converted to carbon dioxide to be measured by infrared absorption. Neither CHN method is suitable for the analysis of organic substances which contain fluorine, phosphorus, silicon, or most metallic elements. 

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