Microdetermination of Lactic Acid in Urine

Abstract

This work was initiated to fill a need for a reliable method for the determination of lactic acid in urine samples of limited quantity, as in the metabolic study of infants.The method described requires a small sample, allows a number of samples to be run simultaneously, and gives a standard deviation of 5.5% for a single run, which is sufficiently precise for biological studies. Ten to 40 micrograms of lactic acid may be determined. Acetaldehyde, the oxidation product of lactic acid under the conditions employed, is isolated from substances interfering with the extremely sensitive color reaction. An apparatus devised to achieve this end has possible application to problems of similar nature. THE procedures for the determination of lactic acid in urine published prior to 1927 were inadequate, according to

Microdetermination of Acetone in Biological Fluids

“…Because all steps are carried out in the same photometer tube, a high degree of precision has been achieved. The feasibility of simultaneous analysis of multiple samples was made possible by the modification of a unique apparatus described previously for the transfer of material by diffusion (15).…”