Diphenylamine as colorimetric agent in the determination of glycogen

✍ Scribed by Boettiger, Edward G.

• Publisher: Wiley (John Wiley & Sons)
• Year: 1946
• Tongue: English
• Weight: 359 KB
• Volume: 27
• Category: Article
• ISSN: 0095-9898
• DOI: 10.1002/jcp.1030270102

✦ Synopsis

The determination of tissue glycogen involves two processes, separation and chemical analysis. Pfliiger 's method of precipitation with alcohol from an alkaline tissue digest is the standard separation procedure. The quantity of glycogen present is measured by methods requiring long continued acid hydrolysis, neutralization, and finally determination of the reducing power of the hydrolysate. I n the present method glycogen is measured oolorirnetrically in one step and the analysis time shortened by several hours.

Alcohol solutions of diphenylamine and concentrated HC1 react strongly with levulose (Corley, '29). This reaction has been used for the determination of inulin, a polymer of levulose (Alving, Rubin and Miller, '39). I n this method hydrolysis of the inulin and the reaction of levulose with the di- phenylamine reagent are carried out in a tightly sealed tube heated to 100°C. Harrison ( '42) has simplified the procedure by using glacial acetic acid as solvent for the diphenylamine. With this reagent the reaction is completed in a shorter time and the tubes may be heated, unsealed, without undue evaporation of the solvent. REACTION O F DIPHENYLAMINE REAGENTS W I T H I N U L I N AND GLYCOGEN Herbert ( '38) studied the reaction of an alcohol-diphenylamine reagent with levulose and glucose. The reaction with * This work was supported by the Bressler Fund of the School of Medicine of the University of Maryland, and accomplished with the technical assistance of Leah Miller Proutt.