A colorimetric method for the determination of pentoses in the presence of hexoses and uronic acids

Abstract

A method using an aqueous soln. of aniline, acetic acid and oxalic acid for the colorimetric estimation of pentoses in the presence of large amts. of other sugars is described. It is suitable for the detn. of 10-100 ug. of xylose. Glucose gave about 2% and galactose and galacturonic acid about 5% of the color intensity from an equal wt. of xylose. Interference by other sugars tested was less than 1%. The effect of varying conditions on the specificity and sensitivity of the reaction was determined and optimal conditions are described. Increased temp., time of development and concn. of aniline all affect color development by the sugars examined, but not equally. The presence of oxalic acid increases the specificity of the test. The color formed is not due to furfural.