Application Of New Extraction Technology Based On Displacement Reaction In Trace Lead Element Analysis

Human daily life and the development of industry and agriculture have brought a heavy burden to our fragile environment. The concentration of heavy metals in the environment is far more than the natural background levels which is a serious threat to our health. Lead is an element without any physiological role to human body and would bring seriously damage to the central nervous system. Because of the affinity and accumulation of lead elements, it can be absorbed by human body via the respiratory systems digestive system and skin, causing great harm. WHO prescribed that the human intake of lead should not exceed0.025mg kg-1, the content of lead in drinking water should not exceed0.01mg L-1. In order to monitor the concentration and distribution of lead, we usually need to analysis the actual samples. But the concentration of target analyte in actual samples is generally ng mL-1or ng L-1, the instrument detected should couple with sample pretreatment technology to meet the requirements of tests.Modern extraction technology is developing towards to environment friendly. Dispersive liquid-liquid microextraction (DLLME) and magnetic solid-phase extraction (MSPE) are two model sample pretreatment technologies developed in recent yeas with the advantage of simple operation, less organic reagent consumption and so on. Ionic liquids (ILs) is a kind of green solvent with the advantage of non-toxic, no significant vapor pressure, environment-friendly and the extraction of many organic and inorganic compounds which is an alternative to the traditional organic solvent. The displacement reaction theory is applied into DLLME and MSPE, improved the anti-jamming capability of methods, has a broad application prospects. In this paper, three fast, green, effective, easy sample pre-treatment methods based on theory of displacement reaction are applied in the extraction of lead in water samples with complex matrix. The main contents of work are summarized below:1、Based on dispersive liquid-liquid microextraction (DLLME) method, using one-step displacement theory, for the determination of trace lead in water samples by GFAAS. Ultrasound-assisted surfactant-enhanced emulsification method was used instead of dispersion solvent. OP-10as emulsifier, chlorobenzene as extraction solvent was used in the equipment. And other parameters which affect the efficiency of this method were optimized.2、Ionic liquid as extraction agent, ethanol as dispersants, using ionic liquids extraction based on one step displacement dispersion liquid-liquid microextraction technique for the determination of trace lead in water samples.3、Based on magnetic dispersive solid-phase extraction(MDSPE) and displacement theory, using the extraction effect of ionic liquid, we synthesized Fe3O4-IL magnetic particles, and applied in the extraction of trace lead in water samples. After optimize the various parameters, we apply this method in the determination of trace lead in water samples.