Determination of urinary glucose by fluorescence spectroscopy ofcurcumin using fenton reaction

Abstract

This research presents an alternative method to determine glucose level in human urine based on the glucose oxidase reaction and Fenton reaction. Hydrogen peroxide produced in the reaction between glucose oxidase and glucose would react with ferrous ion via Fenton reaction. The products of Fenton reaction including hydroxyl radicals and ferric ions further reacted with curcumin through oxidation reactions and complex formation, respectively. The fluorescence intensity of curcumin decreased with an increase of hydrogen peroxide or glucose concentration. The effects of various parameters were investigated including HCl concentration, reaction time periods, quantity of reagents and time periods for glucose oxidase reaction. Moreover, the urine matrix effect and potential interfering species were also studied. As a result, the urine matrix did not have impact on glucose detection after a 2-fold dilution of urine sample. The time period required in glucose oxidase reaction and Fenton and curcumin reaction were both 30 minutes. By using the proposed condition, the linear range for glucose determination was 0.30-1.40 mM with the limit of detection and quantification of 0.10 and 0.30 mM, respectively. The co-existing species in urine sample did not affect the determination of glucose except ascorbic acid. The tolerant value of ascorbic acid in urine for glucose analysis by the proposed method was 12.5 mg/L. Moreover, the analytical results obtained by using the proposed method in the analysis of urine samples were not significantly different from the results observed by the standard hexokinase glucose-6-phosphate dehydrogenase method. The percent of relative standard deviation of glucose analysis by using the proposed method were found in the range of 0.9-3.9%. The proposed method was successfully applied to detect glucose in human urine samples with acceptable accuracy and precision.