Über die Genauigkeit der Brenztraubensäure-Bestimmung als 2,4-Dinitrophenylhydrazon

Summary

The accuracy of direct colorimetric estimation of pyruvic acid in the blood has been controlled by the quantitative chromatographic method. To do this it was indispensable to elaborate a new procedure for the quantitative chromatography, since without certain precautions there arose considerable losses owing to the sensitivity of the 2,4-dinitrophenylhydrazone of pyruvic acid to light, temperature, solvents or acids. Avoiding these possibilities of error there still remained a difference of about 20% between the two procedures which could be explained as the result of the formation of two isomers of 2,4-dinitrophenylhydrazone in addition to a smaller purely technical loss. This difference could be corrected by estimating the yield of known quantities of added pyruvate, and as a final result satisfactory agreement between the two methods has been achieved. The direct colorimetric estimation of pyruvic acid as 2,4-dinitrophenylhydrazone is sufficiently specific; it includes no appreciable quantities of other keto-acids and furnishes reliable values.