Determination of Glucose Oxidase Activity of Flour Additive by Fluorescence Quenching Method

Abstract Glucose oxidase can catalyze the reaction of glucose to produce hydrogen peroxide, and hydrogen peroxide reacts with excess I⁻ anions in dilute sulfuric acid solution to form I₃⁻. The I₃⁻ combines with Rhodamine 6G to form association which result in fluorescence quenching. Effect of glucose oxidase on fluorescence of Rhodamine 6G, a new method with high sensitivity and good selectivity for the determination of glucose oxidase activity was established. Under the optimal conditions, the linear range of the method is 1.0×10⁻ ⁴-1.0×10⁻ ¹ U/mL, and the detection limit is 9.0×10⁻ ⁵ U/mL. This assay was applied to the determination of glucose oxidase activity in the food additives samples with satisfactory results, the recoveries obtained were 95.33%-102.5%.