Ratio-type fluorescent probe for detecting thiocyanate ions as well as preparation method and application of ratio-type fluorescent probe

The invention discloses a ratio type fluorescent probe for detecting thiocyanate ions and a preparation method and application thereof.The probe takes rhodamine-B-isothiocyanate (RITC) functionalized polyamide-amine dendritic macromolecule PAMAM as a base material, gold nanoparticles AuNPs are packaged in the base material, the gold nanoparticles AuNPs act with a block copolymer pMAA-b-PEO to form dendritic micelles, and the dendritic micelles are used for detecting the thiocyanate ions. The ratio-type fluorescent probe is formed after the reaction is completed, and the probe is marked as pMA-R-PAMAM-Au. The invention further discloses a method for detecting the thiocyanate ions, based on a resonance fluorescence quenching mechanism of AuNPs and RITC, the thiocyanate ions can selectively etch AuNPs and recover the fluorescence characteristic of the RITC, and meanwhile, the fluorescence of the composite material cannot be greatly changed due to the addition of other anions. Therefore, the pMA-R-PAMAM-Au dendri