石墨烯量子点-银纳米颗粒复合物用于过氧化氢和葡萄糖比色检测

Preparation of Graphene Quantum Dots/Ag Nanoparticles Nanocomposites for Colorimetric Detection of H_2O_2 and Glucose

以石墨烯量子点(GQDs)为还原剂和稳定剂在其表面原位生长银纳米粒子(AgNPs),制备了具有良好分散性的GQDs/AgNPs纳米复合物,其粒径小于30 nm。GQDs/AgNPs纳米复合物具有类过氧化物酶的催化活性能有效催化H_2O_2氧化3,3',5,5'-四甲基联苯胺(TMB)并发生显色反应。稳态动力学分析表明GQDs/AgNPs催化动力学遵循典型的Michaelis-Menten模型,其催化机理符合乒乓机制。与辣根过氧化物酶(HRP)相比,GQDs/AgNPs纳米复合物具有更强的亲和性。基于GQDs/AgNPs的催化活性和葡萄糖氧化产生H_2O_2的原理建立了H_2O_2和葡萄糖的比色检测方法,检出限分别为0.18和1.6μmol/L。将本方法应用于血浆中葡萄糖的检测分析,结果与标准方法相符。

Graphene quantum dots/Ag nanoparticles nanocomposite（GQDs/AgNPs） was prepared via in-situ growth of AgNPs on the surface of GQDs,in which GQDs served as both reducing agent and stabilizer.The as-prepared nanocomposites were mono-dispersed with an average diameter of less than 30 nm.The obtained GQDs@ AgNPs nanocomposites exhibited excellent intrinsic peroxidese-like activity,which could catalyze the oxidization of 3,3＇,5,5＇-tetramethylbenzidine（TMB） by H2O2 to produce a colour product.Steady-state kinetic assays showed that the catalytic activity of GQDs/AgNPs towards H2O2 fitted well with typical Michaelis-Menten kinetic model,followed by the ping-pong mechanism.Compared with the horseradish peroxidase（HRP）,GQDs/AgNPs showed higher affinity towards TMB and H2O2 substrate.Based on the intrinsic peroxidese-like activity of GQDs/AgNPs nanocomposites and the production of H2O2 after the oxidation of glucose,a colorimetric method was developed for the detection of H2O2 and glucose,along with detection limit of 0.18 μmol/L and 1.6 μmol/L,respectively.The present method was applied to the detection of glucose in human serum,and the obtained results agreed with that obtained by reference method.