一种水溶性超分子荧光探针对农药缩节胺的识别

A Turn-on Supramolecular Fluorescent Probe for Sensing Mepiquat Chloride

八元瓜环(Q[8])能使碱性黄T(thioflavin T,ThT)荧光增强,在荧光探针(Q[8]/ThT)中加入缩节胺(mepiquat chloride,MC)后荧光强度又逐渐降低,因此,利用超分子配合物Q[8]/ThT的荧光“开-关”效应,设计了一种超分子荧光探针(Q[8]/ThT),实现了MC的快速检测。研究结果表明,该探针在pH=7的Tris-HCl溶液中对MC具有很好的识别能力,且在一定浓度范围呈线性关系,其检出限为3.6×10^(-8) mol/L。此外,通过核磁共振波谱(1H NMR)和等温滴定量热法(isothermal titration calorimetry,ITC)考察了探针对MC的识别机理,推测出MC的加入与超分子荧光探针(Q[8]/ThT)中Q[8]的端口发生了主客体相互作用,即Q[8]、ThT和MC形成了2∶2∶2的作用模式。

Cucurbit[8]uril(Q[8])could increase the fluorescence of thioflavin T(ThT),the intensity of which is gradually decreased after adding mepiquat chloride(MC)to the fluorescent probe(Q[8]/ThT).Thus,a kind of supramolecular fluorescent probe(Q[8]/ThT)was designed through the fluorescence“on-off”effect of the supramolecular complex of Q[8]/ThT,which could realize the rapid detection of MC.The research results of the study showed that the fluorescent probe had a good ability to recognize MC in a Tris-HCl solution of pH=7,and had a linear relationship within a certain concentration range,with a detection limit of 3.6×10^(-8) mol/L.Furthermore,the recognition mechanism of the probe to MC was investigated through 1H NMR spectroscopy and isothermal titration calorimetry(ITC),and it was inferred that the addition of MC had a host-guest interaction with the two open portals of Q[8]of the supramolecular fluorescent probe(Q[8]/ThT),namely,Q[8],ThT,and MC formed a 2∶2∶2 mode of action.