Construction Of Fluorescent Nanomaterial Sensing System For Detection Of Tetracycline And Hg²⁺

Nanomaterials have unique optical,magnetic and thermal conductivity properties and unique shape,size and structure control capabilities.With the stable fluorescence performance and high fluorescence intensity,fluorescent nanomaterials are very advantageous in the construction of fluorescent sensing systems.The fluorescent nanomaterial sensing system constructed by fluorescent nanomaterial has been widely used in environmental detection,biomedical analysis and other fields.On this paper,gold nanoclusters modified by threonine?Thr-AuNCs?and two kinds of carbon dots?CDs?were used as fluorescence analysis signals,and the highly selective fluorescent sensing systems for rapid and sensitive detection of tetracycline and Hg²⁺were prepared by combining molecular imprinting technology and chemical modification methods.The main research contents are as follows:?1?Molecularly imprinted fluorescent sensing system based on Thr-AuNCs for tetracycline detectionA core-shell nanomaterial sensing system with SiO₂ nanomicrospheres as the supporting core was synthesized by sol-gel method for selective detection of tetracycline.First of all,Thr-AuNCs modified by threonine was synthesized and then MIPs was prepared with SiO₂ as supporting core.The synthesized imprinted material had a lots of recognition sites that matches tetracycline exactly.Using the fluorescence intensity quenching caused by electron transfer,tetracycline can be selectively recognized among a variety of antibiotics within 8 min.In the concentration range of 1¹00?M,tetracycline caused a significant decrease in the fluorescence intensity of the sensing system,and in the range of 1¹0?M and 10¹00?M it showed good linear relationships,the correlation coefficients were 0.9969 and 0.9911 respectively,the detection limit was 26 nM.So it can be a rapid and sensitive selective method for detection of tetracycline.?2?CDs-based ternary emission fluorescent sensing system for detection of Hg²⁺A nano ternary emission fluorescent sensing system based on two kinds of CDs was designed for selectivity detection of Hg²⁺.Single-emission carbon dots and double-emission carbon dots were mixed in proportion,and the resulting mixture had three fluorescence emission peaks at the same excitation,which were located at 450 nm,525 nm and 601 nm,respectively.After the addition of Hg²⁺,the fluorescence intensity at 450 nm and 525 nm were reduced and the fluorescence intensity at 601 nm unchanged,forming a ternary emission ratio-type fluorescent sensing system.The sensing system can detecte Hg²⁺in the range of 0.4⁵?M rapidly and selectively,with a detection limit of 3.11 nM.Compared with other detection systems,the fluorescent materials used are low toxicity carbon dots,which are more economical and environmentally friendly and are conductive to further application.