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美國CHEMetrics K-8540 總磷離子儀器比色分析包
Phosphate, Total
Instrumental Kits
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Method
Phosphorous occurs in natural waters and wastewaters mainly as phosphates and is widely distributed in the environment as orthophosphates, condensed phosphates (pyro-, meta- and other polyphosphates), and organically-bound phosphates. Sources of phosphate include surface-applied fertilizers, commercial cleaning preparations, boiler water conditioners, and drinking water treatment chemicals. Phosphorous is an essential nutrient for the growth of organisms. However, discharge of wastewater containing high levels of phosphate may cause excessive algae growth which causes taste and odor problems in drinking water supplies and oxygen depletion and death of aquatic organisms in surface water. Therefore, control and monitoring of phosphate concentrations in wastewater are critical.
The Ascorbic Acid Method
References: APHA Standard Methods, 21st ed. Method 4500-P B.5&E (2005). USEPA Methods for Chemical Analysis of Water and Wastes, Methods 365.2 and 365.4 (1983). Murphy, J., and Riley, J.P., "A Modified Single Solution Method for the Determination of Phosphate in Natural Waters", Anal. Chim. Acta., Vol. 27, p. 31-36 (1962).
The Total Phosphate Vials measure those forms of phosphate that are converted to orthophosphate during an acid oxidation digestion. This includes many organically bound and condensed phosphates. Once converted to orthophosphate, the reaction with molybdate in acidic solution produces phosphomolybdic acid, which is reduced by ascorbic acid to a blue complex. Results are expressed as ppm (mg/L) P or PO4
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