Abstract
The blood is laked with eight volumes of water and the protein is then precipitated by the addition of one volume of 1:1 nitric acid. In a portion of the filtrate chlorides are determined gravimetrically by precipitation with silver nitrate and filtering on a Gooch crucible. The excess of silver in the filtrate is removed with hydrochloric acid and the resultant filtrate and the remainder of the blood filtrate are combined and treated with copper nitrate and perchloric acid, evaporated to dryness and then to blackness. 1 The residue is treated with concentrated hydrochloric acid, again evaporated to dryness and then dissolved in dilute hydrochloric acid. Sulfates are precipitated with barium chloride and the filtrate is made ammoniacal, then acid with acetic acid and phosphates are precipitated with ferric chloride. The precipitate is dissolved in nitric acid and the phosphoric acid is precipitated with ammonium molybdate and the yellow precipitate is titrated. The filtrate from the ferric acetate precipitate is treated with sulphuric acid to remove the barium and with hydrogen sulfide to remove the copper and the filtrate is evaporated to small volume. Calcium is precipitated in a centrifuge tube as oxalate, washed and titrated. The supernatant liquid and washings are evaporated, heated to remove ammonium salts and the magnesium is precipitated in a centrifuge tube as magnesium ammonium arsenate. This is washed and then dried, in vacuo, over sulfuric acid. It is dissolved in acid, transferred to a distillation flask and the ammonia determined by distillation and Nesslerization. The supernatant liquid and washings are treated with hydrochloric and hydrobromic acids, evaporated to dryness, freed of ammonium salts and arsenic, sulfuric acid is added and the potassium and sodium are weighed as mixed sulfates in a platinum dish.
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