Rapid Specific Method for Determination of Aldosaccharides in Body Fluids

Abstract

IN the clinical field it is of importance to have a rapid and exact method for glucose determinations. In order to avoid the non-specific reduction methods, a coupling reaction was worked out utilizing the conjugation of aldoses and ketoses with meta-aminophenol in acetic acid. After some preliminary experiments¹, a routine method was described². The method has been used for some time in this laboratory and has proved satisfactory; but, because of the necessarily long boiling time of 30 min., and the fact that the whole range of urine sugar concentration cannot be read without dilution of the urine, it was considered an advantage to have a reagent giving a more rapid reaction and a wider range. Many aromatic amines have been tested; of these, one of the most suitable was ortho-toluidine, for which the optimal boiling time is 8 min. (Fig. 1). It gives a blue-green colour with maximum absorption at 6250 A. and is fairly specific for aldosugars (Fig. 2). Blood treated with glucose oxidase gave readings corresponding to 0–4 mgm. glucose per 100 ml. blood. With this reagent glucose quantities of 10–400 µgm. can be read directly in a Beckman B photometer.