Colorimetric detection of 1,5-anhydroglucitol based on graphene quantum dots and enzyme-catalyzed reaction

Early diagnosis of diabetes yields significant clinical benefits. The serum level of 1,5 anhydroglucitol (1,5 AG) has been a new biochemical marker for postprandial hyperglycemia In this study, a simple colorimetric method for 1,5 AG detection has been designed based on highly efficient peroxidase mimetic activity of GQDs and enzyme-catalyzed reaction. By the catalytic action of pyranose oxidase (PROD), the 1,5 AG was oxidized to 1,5 anhydrofuctose and H2O2. The GQDs in the presence of H2O2 exhibited highly efficient catalytic activity toward the oxidation of 3, 3', 5, 5', tetramethylbenzidine (TMB) to a blue colored product. The influence of relevant experimental variables was optimized. A linear relationship of optical signal with the concentration of 1,5 AG in the range of 20.0-100.0 mu g/mL with the regression correlation coefficient of 0.9985 was obtained which could be monitored by colorimetry detection. The limit of detection (LOD) for 1,5 AG detection was approximately 0.144 mu g/mL All in all, the proposed 1,5 AG detection system based on GQDs and PROD-catalyzed reaction showed better performances with simple operation, low-cost, higher selectivity. (C) 2018 Elsevier B.V. All rights reserved.