Synthesis And Application Of Fluorescent Probe For Hg²⁺ Based On Polymeric Particles

The problem of heavy metal ions pollution has become more and more serious. For heavy metal ions, it is difficult to recycle and easy to accumulate in human body. Thus, it is meaningful to prepare the detection of heavy metal ions with high selectivity, high sensitivity, low detection limits. A small molecule fluorescent probe with visualization, detection speed, high sensitivity and low limits of detection, has a significant advantage in terms of detection of heavy metal ions. The small molecule fluorescent probes can be grafted on the surface of the microspheres with functional groups and it would be easy detected in biological systems. However, if the magnetic particles can be introduced in the microspheres, the responsive nanomagnaetic flurecent may be used as an adsorbent and detection for heavy metal ions to a certain extent. Here, we designed and synthesized two polymer microspheres in the Hg2+ fluorescent probe, and we charactered the chemical composition, structure, mechanism, pH response, time response, adsorption properties and detect the fluorescence intensity with the ion concentration in the aqueous solution, meanwhile we detected the Hg2+in MC-3T3 cells by fluorescence detection. Specific process is as follows:(1) Two kind of Hg2+ fluorescent probe which has specific response was synthesized with rhodamine 6G, namely RH6G-CHO and RH6G-S. They all have good water solubility and the chelation ability of Hg2+.We charactered those material by’HNMR, MS et, the results indicated that the former is not reversible probe and would be hydrolysis in the case of Hg2+, the latter belongs to the reversible probe and would fluorescence fade with the addition of EDTA.(2) The good water-soluble Poly (St-GMA) was prepared by St and GMA in soap-free emulsion polymerization. The Leuckart reaction occurred between aldehyde and a secondary amine RH6G-CHO fluorophore on the nanoparticles to avoid the effects of Hg2+ identification process since the steric hindrance.The results showed the material was succefully made and it could response to a wide pH range, the maximum fluorescence intensity would be reached in 20 min. there is a linear correlation between the intensity of fluorescence and the concentration of Hg2+. When the epoxy monomer GMA is 13%, the rate of up to probe grafted reached 42.4 mg/g. TEM tests was used to characterize the morphology of the particles, the experiments show that the cell-based fluorescent nanoparticle probes have very RFNPs good biocompatibility and low toxicity,it has promosing to be used in detection biological systems of Hg2+.(3)The Fe3O4 nanoparticles was synthesized by conventional co-precipitation method. The nanoparticles modified by oleic acid and undecylenic acid could be coated by GMA and St. Finally, RH6G-S fluorescent was grafted on the material to prepare the fluorescent magnetic nanopaticles FMNPs. The rusults charectered by FTIR, XRD, XPS and other tests show the Hg2+ can be detected when the concentration as low as 0.79 μM in solution. The probe has high sensitivity, selectivity, good anti-interference, pH response range between 4～ 9, the respond time is 3 min. It can be used for water samples Hg2+ real-time fast testing and has a certain absorption capacity. The equilibrium adsorption capacity is up to 12.20703 mg/g. Since the superparamagnetic, the probe can be recycled and reused.