title: Direct complexometric titration of calcium phosphates.
abstract: Calcium was determined in calcium phosphate samples by dissolving the sample in hydrochloric acid, adding hydroxynaphthol blue indicator and triethanolamine, adjusting the pH to 12.3--12.5 with potassium hydroxide solution, and titrating with standard disodium ethylenediaminetetraacetate solution. Time can be saved and the formation of a precipitate (which dissolves readily during the titration) can be avoided by adding at least 85% of the amount of complexing agent required for titration before adjusting the pH.
mesh_terms: D002118:Calcium / Q000032:analysis; D002130:Calcium Phosphates / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D008722:Methods; D013607:Tablets / Q000032:analysis
chemical_list: D002130:Calcium Phosphates; D013607:Tablets; D002118:Calcium