The Preparation Of Environmentally Friendly Fluorescent Polymer Probe And Detection Of Heavy Metal Ions In Water Samples

In recent years, environmental issues have always been the focus of the people. Atthe same time, the rapid development of China’s industry also caused seriousenvironmental pollution, heavy metal ions pollution in the oceans, rivers and lakes isone of them. In the life sciences, biomedicine and environmental sciences and otherfields, heavy metal ions play an important role. So studying a real-time detection andcontrol methods of heavy metal ion content have extremely important practicalsignificance. Palladium is widely used in fuel cells, crowns and jewelry and so on,which will lead to serious palladium ions residues. Palladium will cause seriouspollution of soil and water systems. Mercury pollution has been the focus of pollutioncontrol, because after mercury ions get into the body, causing serious damage to thebody system. Therefore, the content of this paper has two main parts, the first part,based on poly(vinyl alcohol)/3-poxypropoxy fluorescein (PVA-EPF) has the responseproperty for Pd2+, so we established a detection method for Pd2+in water samples. Thesecond part, PVA-SH-CdS QDs has the response property for Hg2+, so we establishedan efficient detection method for Hg2+in water samples.The paper consists of three chapters, the main research contents as follows:The first chapter, literature review. Mainly introduces the significance andmethods of detection of metal ions, fluorescence spectroscopy analysis, metal ionfluorescent probe; the basic principles and the basic concepts of fluorescence; theresearch progress of the fluorescent polymer, The preparation method of thefluorescent polymer as well as the application of fluorescent polymers in fluorescentprobe technique, fluorescence sensors and fluorescence thermometer; the definition ofquantum dots, characteristics, surface modification and the application of quantumdots in the field of photoelectric, biomedical, analysis testing.The second chapter, through the method of chemical bonding, using fluorescein asa fluorescent small molecule with epichlorohydrin to synthesize3-poxypropoxyfluorescein (EPF) which containing active group. Then through the ring-openingreaction, making the3-poxypropoxy fluorescein grafted polyvinyl alcohol (PVA) onthe side chain, successful synthesized environmentally friendly, cheap, water-soluble,easy film-forming metal ion response of novel fluorescent polymer poly(vinyl alcohol)/3-poxypropoxy fluorescein(PVA-EPF). The structure and properties of EPFand PVA-EPF were characterized, using nuclear magnetic (HNMR), massspectrometry (HR-MS), infrared spectroscopy (FI-IR) and fluorescence spectra method.Then, through measuring the fluorescence of PVA-EPF, identified that the material hasgood selectivity and sensitivity to Pd2+in aqueous solution, and further analyzeinfluence of the material concentration, reaction time and temperature, and pH value ofthe system on the fluorescence intensity. Finally, based on PVA-EPF in wavelength of520nm quenching of the fluorescence signal, and the degree of quenching with Pd2+concentration had good linear change, established a kind of environmental friendly,cheap, simple, rapid, sensitive detection of Pd2+fluorescence spectrum analysisdetection method in real water samples. The detection limit of this method is2.8×10-8mol/L, the linear range of determination of Pd2+is5×10-8～6×mol/L10-5mol/L, thelinear correlation coefficient is0.993.The third chapter, through the method of chemical bonding, using mercaptoaceticacid reacts with PVA under acidic conditions, thus made water-soluble thiol polyvinylalcohol (PVA-SH). Then add the chromium acetate (Cd(CH3COO)2·2H2O) andSodium sulfide nonahydrate (Na2S9H2O), made water-soluble PVA-SH-CdS QDs whichmodified by PVA-SH in the absence of air. The structure and properties of PVA-SHand PVA-SH-CdS were characterized, using infrared spectroscopy (IR),thermogravimetric analysis (TG-DTA), X ray analysis (XRD), gel permeationchromatography (GPC), transmission electron microscopy (TEM), fluorescencespectrum, respectively. Then, the fluorescence of PVA-SH-CdS QDs aqueous solution,solid, and film was measured, identified that the quantum dot has fluorescence and theresponse property for Hg2+. Finally, based on PVA-SH-CdS QDs in520nmwavelength fluorescence quenching of the signal, and the quenching degree increasedwith Hg2+concentration linearly, established a rapid, environmentally friendly,low-cost detection method of Hg2+in real water samples by fluorescence spectrometryanalysis method...