亜硝酸コバルト法に依る加里の定量法に就て

概要

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Various method for the determination of potassium by precipitation as the cobaltinitrite have been published, yet no one so far proposed gives a precipitate of potassium cobaltinitrite of strictly constant composition for a wide range of potassium concentration ; furthermore, its error in duplicate determination seems to be large. Therefore, the present authors intended to avoid these defects by studying especially the conditions of precipitation following JENDRASSIK'S technique chiefly. Studies were made, especially, to elucidate if the temperature of precipitation might affect the composition of a precipitate, as has been suggested by Piper and others, but no accurate data about this subject have not been yet published. Therefore, some experiments were made, as shown in Table I, on the effects of temperature of precipitation and duration of heating on the composition of the precipitate, according as separate reagents NaNO_2,Co(No_3)_2,CH_3COOH, are successively added or they are previously mixed before addition. The results are given in Table I. On the basis of these studies, a new modified method proposed is as follows.
社団法人日本土壌肥料学会の論文
1936-12-15