The Determination of Inorganic Phosphate in Urine by Alkalimetric Titration,

In an investigation of the excretion of phosphate and other substances in short periods (chiefly of 1 hour) now being conducted in this laboratory, it has been necessary to make many inorganic phosphate determinations with limited quantities of urine. In most instances the accuracy possible with colorimetric and nephelometric methods has been sufficient, and, after a considerable amount of time had been spent in attempting to adapt then existing methods to the purpose at hand, the routine determinat,ions were for a t.ime made by precipitating the phosphate with magnesia mixture and determining the phosphate content of the redissolved precipitate nephelometrically (with strychnine molybdate). The necessity of resorting to this none too satisfactory arrangement has now fortunately been removed by the calorimetric method recently devised by Bell and Daisy,’ and this has since been used instead. In view of the empirical