Spectroscopy Analysis And Determination Of Mercury(â…¡) In Environmental Water Sample

Mercury(Ⅱ) is an important pollutants and can cause serious harm to human health. A major source of human exposure stems from contaminated natural waters, so the determination of mercury(Ⅱ) in environmental water is very important. In this paper, resonance light scattering(RLS) and absorption analytical method of mercury(Ⅱ) were developed. The reaction mechanism were also investigated and the methods have been applied to the determination of mercury (Ⅱ) in environmental water samples. It is very important for studying on the hazards of mercury ion in the environment and human body. Specific contents are as follows:(1) At pH3.29acidic medium, the interaction of Hg (Ⅱ) with Thioacetamide (TAA) occurs and results in greatly enhanced Resonance Light Scattering (RLS) signals characterized by a peak at379.0nm. Experiments show that the enhanced RLS signals intensity (ΔIRLS) at379.0nm is proportional to the concentration of TAA. And then a new RLS method for the determination of trace Mercury ions was established accordingly. The linar range is0.2-10.0μmol/L. The limit of detection is0.02μmol/L for Hg(II). In this work, acidity, ionic strength, temperature and coextensing substances interference were also investigated. The method has been applied successfully to the determination of Hg2+in environmental water samples.(2) In acidic medium, a resonance light scattering (RLS) analytical method of Hg(Ⅱ) was established based on the enhanced RLS signal due to the interaction of (1-Hexadecyl)triphenylphosphonium bromide(HTPB) and HgBr42" ion derived from the reaction between mercury ion and excess Patassium Bromide. The enhanced RLS intensity at291.Onm is proportional to the content of mercury (Ⅱ) in a range of0.04～ 1.5μmol/L. The limit of detection(3σ) is4.0nmol/L. In this work, the optimum reaction conditions and the interference of foreign substances of the system were investigated. At the same time, the absorption spectral as well as the reaction mechanism were also be investigated. This method has been successfully applied to the determination of mercury (Ⅱ) in environmental samples with RSD<4.42%.(3) A novel colorimetric detection method for mercury (Ⅱ) with a tunable detection range was developed based on the absorption signal decreasing of murexide due to the specific binding of mercury (Ⅱ) with murexide. The decrease in absorption intensity at520.0nm is proportional to lgcHg2+in a range of50.0-1200nmol/L. The linear regression equation is IA/A0=0.58661gcHg2++0.6833(c,10-7mol/L). The correlation coefficients r is0.9909. The limit of detection (LOD,3σ) is12.7nmol/L. Addition of Hg2+to the solution or the murexide paper strips produce a color change from purple to colorless. Based on murexide colorimetric probe for Hg2+selective recognition, the visual sensing of Hg2+was achieved, In this paper, the optimum reaction conditions and the interferences of foreign substances were investigated. The reaction mechanism between murexide and Hg2+were also investigated. This method has been applied to the determination of mercury (Ⅱ) in mixed samples and laboratory wastewater samples with RSD≤5.0%.