Rapid Glucose Oxidase-Peroxidase Ultramicro Method for Determination of Blood Glucose

Abstract

Abstract A rapid, convenient, and easy ultramicro modification of the glucose oxi-dase-peroxidase method for determining blood glucose is described. The reagent mixture is prepared by mixing phosphate buffer (pH 5.0) with lyophilized enzyme-chromogen (o-dianisidine). To this is added 20 µl of plasma or serum. After 15 min at room temperature the reaction is stopped, and the reaction mixture cleared, by adding 4M HCI. Absorbance is read at 400 nm vs. a reagent blank or, preferably, against a reagent blank containing serum or plasma. The individual (prepackaged) reagents are stable for at least 10 months; the reagent mixture and the color of the acidified reaction product are stable for more than 5 h. Protein precipitation, apparently un-necessary, has been eliminated. Absorbancies obtained by this method are linear for glucose concentrations as great as 300 mg/100 ml. Heparin, Parasepts, and benzoic acid do not inhibit the reaction.