The determination of sugar in blood and spinal fluid with anthrone reagent.

The anthrone reagent of Dreywood (1) has been applied to the determination of blood sugar by Durham, Bloom, Lewis, and Mandel (2), Fetz and Petrie (3), and Zipf and Waldo (4). In the procedures developed by these authors, the heat resulting from mixing sulfuric acid with water causes the reaction to take place. Greater precision is obtained by heating the mixture of anthrone, sulfuric acid, and carbohydrate for a definite time in a constant temperature bath. Scott and Melvin (5) reported that the “heat of mixing” procedure is satisfactory if accuracy no better than ~5 per cent is required. They obtained data showing a coefficient of variation of kO.48 per cent in their method, which involves heating in an ethylene glycol bath at 90” for 16 minutes. In our laboratory a method was developed for the determination of dextran in blood and urine in which a mixture of anthrone reagent and dextran solution is heated in a boiling water bath for a definite time (6). In twelve determinations by this method with dextran solution there was observed a coefficient of variation of kO.36 per cent, and in twelve determinations in which the dextran was precipitated from solution by alcohol the coefficient of variation was f0.56 per cent. Our observations with respect to the precision of the “heat of mixing” procedure, compared with heating for a definite time in a constant temperature bath, are in agreement with the work of Scott and Melvin (5). We have adapted our procedure for the determination of dextran to the estimation of the sugar in blood and spinal fluid. A stabilized anthrone reagent has been developed, and certain findings of interest are reported.