| POPs(persistent organic pollutants, called POPs) refer to the organic contaminants of natural or synthetic which can migrate long distances with a variety of environmental media(air, water, organisms, etc.) and persist in the environment and human body. It has serious harm on the environment and human health. The serious harm to the environment and human health of POPs caused wide public concern in the world, and scholars from various countries are working on solving the problem of pollution of POPs. Therefore, the development of rapid, low cost, sensitive detection method to a variety of POPs is of great importance for environmental protection and human health.In this study, two kinds of novel adsorbent materials were prepared independently: the hydrofluoric acid etching of natural sand porous materials and carbon coated Fe3O4 nanoparticles. Based on the two kinds of adsorbent, we developed the dispersive solid-phase extraction methods, combined with GC-MS/MS, to determinate PCBs and PBDEs in the actual water samples in different locations. The applicability of this method was tested, and its commercial value was discussed. The main research results are as follows:1. The ordinary construction sand as raw material prepared a novel porous material. In first, washed the sand with plenty of distilled water to remove the soil, and then sieved them to obtain uniform particles. Then the uniform sand particles were etched with hydrofluoric acid to form the surface of the porous structure, and after cleaning and drying, the porous adsorbent material was obtained. In this study, a kind dispersive SPE with this novel porous material as absorbent was developed, combined with GC-MS/MS, for the detection of six kinds of PCBs in drinking water. In order to obtain the optimal conditions, we optimized the adsorption conditions(the amount of adsorbents, pH, extraction time and ionic strength) and desorption conditions(desorption time, type of solvent and solvent volume). The method validation and the analysis of real samples were conducted under the optimal conditions. The results showed that the composition of sand significantly changed after etching, and the surface formed into the honeycomb porous structure, so that the material had a good adsorption performance. Compared with the previously reported method, the method based on this material has a lower detection limit. The linear range is between 10-1000 μg/L, and it is sufficient to meet the testing requirements of the general sample. The repeatability of this method is pretty well, but there are some differences between the adsorbent materials synthesized with the sand from different regions.2. At first, nanosized ferroferric oxide(Fe3O4) powders being about 200-400 nm in diameter are synthesized by adding Iron(III) chloride hexahydrate, polyethylene glycol and sodium acetate(Na Ac) into ethylene glycol in order. The second step is to introduce the Fe3O4 nanoparticles in glucose aqueous solution, and then the Fe3O4@C microspheres were synthesized by a hydrothermal reaction. Based on the Fe3O4@C magnetic nanoparticles we developed a dispersive solid-phase extraction method for detecting PBDEs in water. The adsorption conditions(adsorption time, the quantity of absorbent and ionic strength) and the desorption condition(desorption solution) of this method were optimized by response surface methodology and by single-factor test, respectively, to obtain the optimal experimental conditions. Method validation and analysis of real water samples were investigated under optimal conditions. The results showed that, Fe3O4@C magnetic nanoparticles had both of advantages of megnetic microparticles and carbon nanomaterials. They have large specific surface, good chemical resistance, excellent adsorption property and efficiency, and also exhibited superparamagnetism which allowing to separate the adsorbents from water samples quickly with an applied magnetic field. The developed dispersive solid-phase extraction based on the Fe3O4@C magnetic nanoparticles has good recoveries of PBDEs, which is range of 72.8%-97.9% better than some reported methods. |
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