Fluorescence turn-on sensing of thiamine based on Arginine - functionalized graphene quantum dots (Arg-GQDs): Central composite design for process optimization

A low-cost, sensitive and convenient fluorescent probe of highly fluorescent Arginine -functionalized graphene quantum dots (Arg-GQDs) was designed and synthesized by a facile one-pot hydrothermal treatment of citric acid in the presence of Arginine. The fabricated Arg-GQDs with oxygen-rich functional groups exhibit a strong blue emission with 28.3% quantum yield (QY). It is found that such Arg-GQDs with high QY can be used as efficient fluorescent probe for thiamine determination. In the detection, photoluminescence (PL) intensity of the Arg-GQDs was reversibly quenched and recovered by Ag+ and thiamine, respectively. The effect of different parameters were optimized by central composite design (CCD) combined with response surface methodology (RSM). Furthermore, results of CCD were evaluated by standard analysis of variance (ANOVA) to assess the accuracy and suitability of the quadratic model. Under optimal conditions, the fluorescence Off-On process showed a sensitive response to thiamine in the concentration range of 0.1-8.0 mu M with a detection limit of 53 nM. Finally, the Arg-GQDs based fluorescence method was applied to the analysis of thiamine in pharmaceuticals and foodstuff samples with satisfying recoveries for the spiked samples. (C) 2017 Elsevier B.V. All rights reserved.