Dinitrosalicylic Acid: a Reagent for the Estimation of Sugar in Normal and Diabetic Urine

The methods used for the quantitative determination of sugar in urine, including the polariscope, ‘give good results when the amount of sugar present is considerable, but there is always a point where the urine contains so little sugar that the results are dubious. Special met)hods have been published for the determination of sugar in normal urine. Many of these give results that are too high, and others, like the method of Benedict and Osterberg,’ are too long for clinical work. It appeared that some reagent might be found which could be used both qualitatively and quantitatively and which could be applied to both normal and diabetic urine. The author believed that the most suitable substance would be a compound similar to picric acid in that it, would be reduced by glucose to form a highly colored nitroamino compound, but dissimilar to picric acid in that it would neither form colored compounds with acetone or creatinine nor be reduced by urinary constituents other than the sugars. Two nitro compounds have been found which meet most of these requirements; these are 4, 6-dinitroguaiacol and 3, 5-dinitrosalicylic acid.2 Both of these compounds can be used successfully for the estimation of glucose in diabetic urine, but while they are not reduced in the presence of sodium carbonate by any urinary constituent yet tried, with the exception of the