The Separation and Gravimetric Estimation of Potassium

The market value of chloroplatinic acid, particularly under present conditions, is so high as to warrant a careful search for some cheaper reagent for the determination of potassium. Serullas, as early as 1831, proposed taking advantage of the insolubility of potassium perchlorate in concentrated alcoholic solutions and applying it as a reagent for the estimation of potassium. Unfortunately his proposal did not receive the attention it deserved because a convenient method for the preparation of perchloric acid had not at that time been worked out. Lately, Kreider elaborated a method for the preparation of perchloric acid in large enough quantities and in sufficient purity to attempt its use as a precipitant for potassium. Following the treatment suggested by Caspari he obtained very satisfactory results