Mg(OH)2による微量リン酸の濃縮ならびに海水中の無機リン酸の捕集 : リン酸の定量分析(第7報)

概要

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For concentration and separation of a trace of phosphoric acid from disturbing substances, Mg (OH) 2 is used as a collector. The precipitate equivalent to above 7 mg Mg in 100 ml of sample solution is necessary for a quantitative coprecipitation of all the phosphoric acid present. Precipitate is centrifuged, taken up in dilute nitric acid and neutralized with ammonia, and molybdenum blue method is applied on the solution. The presence of Mg2+, NH4 + and NO3- does not interfere the colorimetric determination, and in the case of sea water, Cl- and SO42-, coprecipitated with Mg (OH)2, can be removed to a negregible extent by washing with ammonia. The presence of As (V) and 3 times as much more As (III) than P gives positive error. Organic phosphorus which is partially coprecipitated, has no influence, as it is not decomposed by the above treatment. By this procedure, 250γ of P2O5 in 1001000 ml of sample solution can be determined.
社団法人日本分析化学会の論文