Application Of New Extraction Technology In Trace Heavy Metal Elements Analysis

Nowadays, the pollution of the environment was increasing seriously with the development of the production of technology and industry. Heavy metal pollution was can not be ignored, which contained heavy metals in waste water such as Pb, Cr, Cd.The waste water treated after was still contained heavy metal, which would cause soil pollution, and then it maybe along with the food chain went into the human body, thus accumulated in some important organs, such as the kidney, liver and bone, eventually causing the health system disorders. Lead and chromium attracted much more attention because of their toxicity, they can pass through the human digestive, respiratory system and skin penetratting the body, then absorbed by human body. When the skin was exposed to the Cr (VI), it may cause skin allergies, and even inherited genetic defect; if inhaled, it may be carcinogenic. Pb is an element which serious hazard to the human nervous system and digestive system, and it’s poisoning is permanent. So, strengthen the prevention of environmental pollution in order to prevent the spread of contamination is particularly important. This requires us to analyse water, however, the concentration level of heavy metal elements in real water samples was usually ppb or ppt, it is very difficult using graphite furnace atomic absorption spectrometer to detect directly.Besides,the interference of matrix containing in the actual sample more or less. Therefore, it is necessary to establish a simple and sensitive pretreatment method if we want to detect the heavy metal which exists in the environmental water samples.In recent years, the dispersive liquid liquid microextraction and dispersive solid phase microextraction regarded as kinds of the environmental friendly pretreatment methods were used widely. The advantage of these methods was low cost, simple operation and low pollution. Electro membrane extraction is the extraction technology which was based on the traditional hollow fiber membrane extraction applied with power, it has accelerated the analyte transfer rate; shorten the time of the extraction equilibrium. Surface active agent instead of toxic organic solvent as a kind of the extraction agent reduces the pollution greatly, and it also can be used as stabilizer for the dispersive micro-solid phase. Titanium dioxide (TiO2) nanoparticles has a larger surface area and highly unsaturated. Therefore, its chemical activity is so high that can absorb some metal ions, the adsorption amount is so much and reached adsorption equilibrium in a shorter time.This paper mainly carried out three kinds of novel, fast and simple sample pretreatment technology in separation and enrichment of heavy metal elements, then combined with graphite furnace atomic absorption spectrometer, to application study of heavy metal in environmental water samples (Cr, Pb) detection and analysis the content of them. The main research contents are as follows:1、Electro-membrane extraction combined with GFAAS, established the detection method of trace Cr (Ⅲ) in water sample. The experiment optimized some condition parameters that influencing the extraction efficiency, such as the type of organic solvent,pH of the solution,complexing agent type and extraction time, and applied to analysis the trace Cr (Ⅲ) in the environmental water samples obtaining satisfactory results.2、Using nonionic surfactant as the extractant, analysis the state of chromium valence using cloud point-dispersion liquid liquid microextraction combined with GFAAS determination of trace chromium in environmental water samples. We optimized the conditions of some parameters affecting the extraction efficiency, such as the effect of pH, the concentration of PMBP, the type and concentration of surfactant, and then applied to the analysis of trace chromium in environmental water samples obtaining satisfactory results.3、Using Titanium dioxide (TiO2) nanoparticles as adsorption material, combined the dispersive micro solid phase extraction assisted by surfactant with GFAAS determination of trace lead in water samples. The experiment optimized some conditions parameters that influencing the extraction efficiency, such as pH of the solution, the type and concentration of surfactant, the mass of adsorbent, and applied to the determination of trace lead in environmental water samples with satisfactory results.