A METHOD FOR THE ESTIMATION OF TOTAL BASE IN URINE

Abstract

The investigation of diurnal variations in the excretion of bases (with the exception of ammonia) has received practically no attention.While this might formerly have been due to the fact that suitable methods for the estimation of the important individual non-volatile bases (sodium, potassium, calcium, and magnesium) were not available, that is no longer so.The main deterrent appears to be the large amount of work required for the separate determinations of these four constituents in the many samples of urine involved in most short period metabolism experiments.When, as may often be the case, the information sought is the total equivalent of all four bases, rather than the amount of each one, the magnitude of the task is out of all proportion to the value of the final result, which includes the accumulated errors of the four individual analyses.Since, in the interpretation of the results of such investigations, the equivalent of the chloride content of the urine must ordinarily be subtracted, and since the remainder may be comparatively small, the micro methods so far described are not sufficiently precise to furnish figures for the sum of the bases that have the requisite degree of accuracy.The method described here is designed to accomplish this.Up to the final step in the analysis, it is merely an adaptation of long used schemes for the separation of these bases from other substances.The urine, after being ashed with sulfuric and nitric acids, is treated with ferric chloride to remove the phosphate, and with ammonium acetate to remove the excess iron (as the basic acetate).The filtrate from these operations contains the bases, which are finally obtained as sulfates, free from interfering substances, by ignition with sulfuric acid and then with 55