A Sensitive Colorimetric Method for the Estimation of 2-Deoxy Sugars with the Use of the MalonaldehydeThiobarbituric Acid Reaction

The important role ascribed to 2-deoxyribose in biological systems led us to investigate a novel calorimetric method for the estimation of 2-deoxy sugars.Although a number of analytical methods for the estimation of 2-deoxy sugars have appeared in the literature (1, 2), none have been found entirely satisfactory due to their attendant insensitivity.As a consequence, several investigators have introduced micromodifications involving the use of micro glassware and special equipment (3-5).In a preliminary account ( 6), a sensitive method of estimating 2-deoxyribose was reported which is based on periodate oxidation and estimation of the ensuing malonaldehyde with 2-thiobarbituric acid.Despite the existence of discriminatory color tests for malonaldehyde (7-9) application of these tests to the quantitative estimation of 2-deoxy sugars has not been previously achieved.EXPERIMENTAL Reagents d-Thiobarbituric Acid (0.6 per cent, pH $.O)-To 90 ml. of water, add 0.71 gm. of crystalline thiobarbituric acid1 and 0.7 ml. of 1.0 N NaOH.Solution is facilitated by shaking the mixture in warm water.Adjust the volume to 100 ml. with water and filter the solution.This solution is sufficiently stable at room temperature for at least 30 days.The performance of the reagent is unaffected by appearance of yellow color on standing, but occasional filtration is required to remove traces of sediment.Periodic Acid Reagent-The reagent is 0.025 N periodic acid in 0.125 N sulfuric acid.