Functional Modification Of Magnetic Nanomaterials And Application In Environmental Analysis

Due to their persistence, mobility and bioaccumμLation of organic pollutants, persistent organic pollutions (POPs) are widely existing in environment, wildlife and even human. In view of the potential threat of POPs to the environment and human health, it is of great significance to develop effective analytical techniques to monitor POPs in the environment. But the concentrations of POPs in environment are at trace level, and the composition of environmental samples is very complicated. Modern analytical instruments cannot achieve accurate detection at such a low concentration, and cannot eliminate the interference in the complex samples. Usually, a process of pre-treatment is necessary before detection to enrich and concentrate target analytes. Among the methods of pre-treatment, magnetic solid phase extraction (MSPE) has been developed rapidly in recent years as a novel solid-phase extraction form. Because of its simple operation and good extraction efficiency, MSPE is widely used in pre-treatment of complex environmental samples. This paper aims to develop functional magnetic nanomaterials as sorbents to extract trace level POPs from environmental samples. The main contents are listed as follows:1.1,4,7,10-tetrabenzyl-1,4,7,10-tetraazacyclododecane (TBCD) modified MNPs were synthesized to selectively extract trace level PAHs from enviromental water samples. The detection was completed on HPLC-FLD. Because of the abundant benzyl groups on the surface of sorbent, the TBCD coated MNPs can provide potent π-π stacking interaction with PAHs, which is the main reason for the high selectivity of Fe3O4/TBCD sorbent to PAHs. And the adsorption equilibrium in the extraction process can be quickly achieved due to the good hydrophilicity of Fe3O4/TBCD MNPs. Therefore, the resμLts obtained in this study have high recoveries, good accuracy, lower LOD and shorter extraction time (5min) than those in other MSPE methods.2. Hexadecyl dimethyl amine (HDMA) modified magnetic nanoparticles were prepared and applied in pre-concentration of PFCs in environmental water samples. The detection was completed on HPLC-MS/MS. On the one hand, hexadecyl carbon-chain contributes the material with strong hydrophobicity to enrich PFCs; on the other hand, Quaternary ammonium cationic groups can not only enhance the hydrophilicity of the material, but also improve the selective adsorption ability by electrostatic interaction with the negative charged hydrophilic groups of PFCs. The resμLts showed that HDMA-functionalized magnetic nanoparticles can fastly and efficiently enrich trace level PFCs from environmental water samples with excellent accuracy and precision.3. In this work, we explored the synthesis of a new type of magnetic composite materials. rGO, CNTs and Fe3O4are mutually combined to form a porous material with3D network structure by self-assembly. Huge specific surface area and strong hydrophobic property offer this material with a great application prospect in pre-treatment of environmental samples. The influence of different synthesis conditions on the material structure was investigated in this paper.