Determination of Glucose Based on Carbon Quantum Dots as Peroxidase Mimetic Enzyme / 分析化学

ABSTRACT

Water soluble carbon quantum dots ( CQDs) were prepared by using soot as carbon source. The obtained CQDs showed an excellent intrinsic peroxidase-like activity, which could catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2and thus resulted in color change. Glucose could react with dissolved oxygen to produce H2O2in the presence of glucose oxidase ( GOx) . A colorimetric method using CQDs as peroxidase mimetic enzyme was developed for glucose determination. When TMB was acted as a substrate, the effect of a series of conditions, such as temperature and pH on the catalytic activity of the obtained CQDs, was systematically studied. Under optimal conditions, e. g. pH 3. 5 and temperature 35℃, 0. 5 mmol/L TMB and 1 μg/mL CQDs, the absorbance at 652 nm showed linear response with glucose concentrations ranging from 0. 025 mmol/L to 0. 40 mmol/L, with detection limit of 5. 10 μmol/L (3σ/k). The proposed method exhibited excellent selectivity and the common substances did not interfere with detection of glucose. This method was successfully applied to detect glucose in real samples with recoveries of 95. 0%-105. 1% .