Preparation Of O-phenylendiamine-based Fluorescent Polymers Dots In The Analysis And Application

Fluorescent material have attracted much attention in the field of life science research, such as biological imaging, medical test, fluorescent tags and biological safety, etc. At present, the research of the fluorescent materials mainly include fluorescent dye, semiconductor quantum dots, rare earth compounds and carbon quantum dots. But there were some defects for the current photo-luminescence fluorescence materials, such as fluorescent biological toxicity and preparation cost was high, the quantum yield of carbon quantum dots was low. At the same time, the existing fluorescence analysis technology need to be improved and enhanced. Therefore, development of new type of low toxicity, high stability, low cost, high quantum yield, good biocompatibility and can be used for rapid detection of fluorescent materials have the vital significance. Polymer dots have attracted a great deal of attention in fluorescent probe and biological sensor due to their excellent photochemical stability, long fluorescence life, extraordinary fluorescence brightness, high emission rates, low cytotoxicity and good biological compatibility.O-phenylendiamine contained more active amino and imidogen, could provide more decorate group. This paper used o-phenylendiamine as monomers, chose Rhodamine B, cysteine and phenylenediamine, respectively, the preparation of P（o-phenylendiamine）-Rhodamine B copolymer dots, o-phenylendiaminem-phenylendiamine copolymer dots, o-phenylendiamine-cysteine copolymer dots, and as fluorescent probe successfully applied to the analysis detection. The main content of this paper was as follows:1. O-phenylendiamine（o PD） and Rhodamine B（Rh B） were used as monomers, ammonium persulfate as the oxidant. Photoluminescent poly（o-phenylenediamine）-Rhodamine B copolymer dot（Pp-Rh B dots） was synthesized by one step hydrothermal method. TEM, UV-vis, FT-IR and PL spectrum were used to characterize its shape and structure. And discussed the effect of p H、light、ion concentration on its fluorescence intensity. The average particle size of Pp-Rh B dots was about 1.86 nm, and have high selectivity and sensitivity for NO₂^-, the detection limit was 2.0×10^-11 M, the detection result was much better than other methods. We also discussed the working mechanism of Pp-Rh B dots detection NO₂^-, and because between the Po PD and Rh B photoinduced electron transfer in formation process of Pp-Rh B dots, which resulted in fluorescent quantum yield of Pp-Rh B dots was lower. However, when additing NO₂^-, generation of C–N–NO bond prevented the photoinduced electron transfer between the Po PD and Rh B, which made the fluorescence enhancement, quantum yield was increased. Pp–Rh B dots was used as fluorescent probes successfully applied in NO₂^- detection in the cell.2. O-phenylendiamine（o PD） and m-phenylendiamine（m PD） were used as monomers, does not add any antioxidant or initiator. O-phenylenediaminem-phenylenediamine copolymer dots（OMCP） was synthesized by one step hydrothermal method. TEM, UV-vis, FT-IR and PL spectrum were used to characterize its shape and structure. We also discussed the effect of p H、light、ion concentration on its fluorescence intensity, The average particle size of Pp-Rh B dots was about 6.45 nm, and quantum yield was about 93%. The synthetic OMCP surface was rich in active amino, so when additing metal ion, strong coordination interactions between metal ion and the surface –NH2 of OMCP result in formation metal complex and the fluorescence quenching of OMCP. We found OMCP had high selectivity and sensitivity for Cr⁶⁺, and the detection limit was 1.0×10^-11 M.3. O-phenylendiamine（o PD） and L-cysteine（L-Cys） were used as monomers, ammonium persulfate as the oxidant. O-phenylenediamine-cysteine copolymer dots（OCCP）was synthesized by one step hydrothermal method. The average particle size of OCCP was about 1.9 nm, quantum yield was about 71%. We also discussed the effect of p H and light on its fluorescence intensity. The synthetic OCCP surface was rich in active amino and thiol, sulfur and nitrogen atoms had strong affinity for Hg²⁺, so when additing Hg²⁺, strong coordination interactions between Hg²⁺ and the surface –NH2 and-SH groups of O-Cys resulted in formation metal complex and the fluorescence quenching of O-Cys, the strong interaction force would lead to electron transfer between O-Cys and Hg²⁺. Through the comparative experiments, in a large number of metal ions, OCCP had high selectivity and sensitivity for Hg²⁺, the detection limit was 1.0×10^-11 M.