Abstract
A method using orcinol-ferric chloride-hydrochloric acid-acetic acid reagent was described for the colorimetric determination of pentose, pentosan, or ribonucleic acid. Coloration by this method was 92% in D-xylose and 89% in D-ribose of that of L-arabinose. Pentoses can be determined up to 10∼50μg./ml. Hexuronic acid showed an absorption curve similar to that of pentoses but its coloration was much lower than that of pentoses. Sialic acid shows a color with an absorption maximum at 580 mμ, but its absorbance at 665 mμ, which is the absorption maximum wave length of pentoses, is low. D-Glucose, D-glucosamine, and deoxyribonucleic acid do not undergo this coloration. Other carbohydrates have very little effect on pentose determination. The presence of serum albumin and sodium coloride does not interfere in the coloration. The present method is better in specificity than other methods which have been used until now.
