Design And Sensing Application Of Fluorescent Probes Based On Gold Nanoclusters

Gold nanoclusters（Au NCs）are preferred for fluorescent probe in sensing due to their excellent photostability,fast and sensitive response,low cost,slight toxicity and simple operation.In addition,carbon dots（CD）have received great attention because of their high fluorescence quantum yield,low cytotoxicity and moderate preparation conditions.Many researchers have combined CD and Au NCs together to form a dual-emitting fluorescent probe,to eliminate the disadvantage that single probe was easily affected by environment,opening up new feild for fluorescent probe.In this work,We designed a“off-on”mode and a dual-emitting mode fluorescent probe on Au NCs,respectively,and realized the sensing of anion including Cl O^-and HSO₃^-and tetracyclines（TCs）.The contents are as follows:First,a yellow fluorescent Au NCs with ultra-small size,well-dispersed and stable fluorescence was synthesized by one-pot method,and the selective response to Cl O^-in aqueous solution was achieved,with a detection limit of 2.03×10^-6M.In addition,a"off-on"fluorescent probe for the selective response to HSO₃^-in aqueous solution was designed based on Au NCs-Cl O^--HSO₃^-.The linear range of HSO₃^-was2×10^-6～2×10^-5M,and the detection limit was 2.12×10^-7M.Next,Carbon dots with stable fluorescence and intense blue fluorescence was synthesized by a hydrothermal method.A dual-emitting fluorescent probe（CD-Au NCs）was obtained by mixing carbon dots and gold nanoclusters.Then,the effect of p H on the fluorescence performance of CD-Au NCs was investigated.It was found that CD-Au NCs reached the strongest fluorescence at p H 6,and CD-Au NCs had good selectivity and sensitive response for TC at this p H.The linear concentration of TC ranged from 7.4×10^-7M to 1.1×10^-4M,and the detection limit was 1.5×10^-7M.In addition,compared the response for TC with single CD or Au NCs probe,the dual-emitting fluorescent probe has a wider linear range and higher sensitivity.Then,CD-Au NCs was applied to detect TC in pill sample,the recovery rate was 102%,indicating that CD-Au NCs can detect TC in actual samples.