基于硅量子点电子转移荧光淬灭的2,4,6-三硝基甲苯/2,4,6-三硝基苯酚检测新方法

A Novel Approach to Detect 2,4,6-trinitrotoluene/2,4,6-trinitrophenol Based on Fluorescence Quenching via Charge Transfer of Silicon Quantum Dots

提出了一种基于硅量子点电子转移荧光淬灭检测2,4,6-三硝基甲苯/2,4,6-三硝基苯酚的新方法.在这个工作中,我们制备了一种表面氨基包覆的强荧光、抗光漂白、单分散的硅量子点.TNT/TNP与硅量子点表面的氨基通过化学识别形成稳定的Meisenheimer复合物,从而淬灭硅量子点的荧光并诱导其团聚.硅量子点的荧光强度与TNT/TNP浓度的对数呈线性负相关,TNT和TNP的检测下限分别为50和5 pg/mL.实验证明,该分析方法有较好的选择性并对分析介质的pH值不敏感,有望实现环境中TNT/TNP的实时、现场和超痕量检测.

Due to the significant detrimental effects of nitroaromatic explosive on the environment and human health,sensitive,rapid,on-site and simple detection methods for explosives are in high demand.A novel label-free silicon quantum dots(SiQDs)-based sensor is designed for ultrasensitive detection of 2,4,6-trinitrotoluene(TNT) and 2,4,6-trinitrophenol(TNP).In this work,amino-functionalized SiQDs are obtained through treating the SiQDs with(3-aminopropyl)triethoxysilane(APTES).The amine-coated SiQDs are not only water-stable but also highly luminescent.Based on the dramatic and selective fluorescence quenching of the amine-coated SiQDs due to charge transfer that resulting from the formation of stable Meisenheimer complexes between electron-deficient TNT/TNP and electron-rich primary amine on the surface of SiQDs,an instant and sensitive sensor is developed for the detection of TNT/TNP which is able to not only directly suppress the fluorescent emission intensity of SiQDs but also induce SiQDs aggregation to result in self-quenching of SiQDs.The results reveal that the developed sensor has high sensitivity for the detection of TNT/TNP.As indicated in experimental results,the fluorescence intensity is proportional to the concentration of TNT/TNP.Meanwhile,linear correlations are obtained respectively for the fluorescence signals to the logarithmic TNT and TNP concentration with 6 and 7 order of range and the detection limit of TNT and TNP is 50 pg/mL for TNT and 5 pg/mL for TNP.Further experiments demonstrate that this analytical method is not susceptible to pH and prevent interference from other nitroaromatics or cationic ions.This simple and cost-effective sensor can be used to detect ultra-trace TNT/TNP in groundwater or seawater.Additionally,this sensor strategy may provide a convenient,rapid,highly sensitive and selective assay platform for nitroaromatic explosive.