DETERMINATION OF GLUCOSE IN BLOOD BASED ON THE INTRINSIC FLUORESCENCEOF GLUCOSE-OXIDASE

A method for the determination of glucose based on the alteration of t he intrinsic fluorescence of glucose oxidase during the enzymatic reac tion is proposed. Addition of glucose to a solution containing the enz yme does not immediately alter the fluorescence, which remains virtual ly constant over a given interval, after which it increases sharply an d eventually levels off. The origin of the signal can be ascribed to t he different fluorescence properties of the oxidized and reduced forms of the enzyme. Based on such differences, a mathematical model relati ng the concentrations of glucose, glucose oxidase, and oxygen in solut ion with the time at which the fluorescence change occurs was develope d. The experimental results were consistent with the model's predictio ns. The proposed method allows the determination of glucose over the r ange 5 x 10(-4)-2 x 10(-2) M, with a precision of 2.1% as relative sta ndard deviation. The method was used to determine the analyte in blood with good accuracy and precision.