Alkaline o-Phenylenediamine Method and the Analysis of Starch

Abstract

Reaction of carbohydrate with o-phenylenediamine in alkaline solution (pH 10) at an elevated temperature (100°C) to produce quinoxaline derivatives can be utilized for the analysis of starch and other carbohydrates. The formation of various quinoxalines can be followed by polarography, ion-exchange chromatography, and thin-layer-chromatography, respectively. The reaction mechanisms of amylose and amylopectin with o-phenylenediamine are discussed. Application of the reaction to the determination of number-average molecular weights of amylose and amylopectin is described. The method is also applicable to the determination of carbonyl content of periodate oxidized starches. Applications to other glucans are briefly stated.