Inorganic Phosphorus (P)
For the in vitro quantitative determination of inorganic phosphorous in human serum.
The majority of the body’s phosphorous is found in the bone as hydroxyapatite. The remaining phosphate is resent as inorganic phosphate esters. Phosphorous is involved in the intermediary metabolism of carbohydrates and is a component of other physiologically important substances. Thus, increased serum phosphorous may occur in hypervitaminosis, hyperparathyroidism, and renal failure. Reduced serum phosphorous levels are seen in rickets (vitamin D deficiency) hyperparathyroidism, and Fanconis syndrome.
Inorganic phosphorous reacts with ammonium molybdate in the presence of an acid to form an ammonium phosphomolybdate complex, which absorbs light at 340 nm. This complex is maintained in solution and its absorbance is enhanced by the addition of surfactant. The increase in color is measured spectrophotometrically and is proportional to the amount of inorganic phosphorous present.
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