The Synthesis Of Magnetic Coordination Polymers And Their Application In Environmental Samples Pretreatment

Persistent Organic Pollutants(POPs) has become a global environmental problem for its persistence, bioaccumulation and potential toxicity. It has caused immense suffering in most part of the world, even in the Arctic far away from the sources of pollution. So far, its realistic and potential harm to people’s health and the environment is very serious. There is much interference detecting the polluted environmental samples, such as the complexity of component, low concentration of the target analyte and the unstability of environmental samples. So the pretreatment is always necessary in the analysing process. The traditional pretreatment methods, such as Soxhlet extraction, accelerated solvent extraction and solid-phase extraction, are time-consuming, solvent-consuming and complicated purification. From the idea of Green Chemistry, it is urgent to develop novel techniques. The magnetic solid-phase extraction(MSPE) has been established in order to improve the selectivity and extraction efficiency.The coordination polymers(CPs) have been widely used as adsorbent in modern analytical chemistry because of their excellent advantages. Combined with functional micro- or nano-particles is the latest trend of CPs, which retains the advantages of both coordination polymers and nano-particles. Magnetic coordination polymers have aroused great interest in modern analytical chemistry because of they can be positioned or collected by an external magnetic field. Combined the specialty of magnetic solid-phase extraction and the advantages of coordination polymer, the thesis include the following four parts:Part one: Eight coordination polymers have been synthesized and characterized based on the assembling of aromatic carboxylic, nitroxide radical with metal ions. Their adsorption ability towards polybrominated diphenylethers(PBDEs) in water samples was pre-studied. Three coordination polymer, [Cu-NITp Py-BDC], [Zn- NITp Py-BDC] and [Cu-NITp Py-IPA] are screened out as the final result.Part two: Two magnetic coordination polymers, Fe3O4@[Cu-NITp Py-BDC] and Fe3O4@[Cu-NITp Py-IPA], have been synthesized by mixing method. They were used in MSPE for the detection of seven PBDEs in water with gas chromatography-electron capture detector. A series of experiment conditions affecting the extraction efficiency, such as the amount of CPs, ultrasonic extraction time, p H value, salinity, etc., were investigated. Under the optimized conditions, the credibility was valuated through the precision, detection limit and recovery.Part three: Three magnetic coordination polymers, Fe3O4@[Cu-NITp Py-BDC], Fe3O4@[Cu-NITp Py-IPA] and Fe3O4@[Zn-NITp Py-BDC], have been synthesized by encapsulation method. They were also used in MSPE for the detection of seven PBDEs in water with gas chromatography-electron capture detector. Under the optimized conditions, the credibility was valuated. Compared with the mixing method, this method showed lower detection limit, better recovery and more repeat utilization, but the larger amount of magnetic coordination polymer was needed.Part four: The magnetic coordination polymer Fe3O4@[Cu-NITp Py-BDC], which synthesized by encapsulation method, was used in MSPE for the detection of hexachlorocyclohexane(HCHs) and dichlorodiphenyltrichloroethane(DDTs) in water with gas chromatography-electron capture detector. The result confirmed that Fe3O4@[Cu-NITp Py-BDC] couldn’t adsorb HCHs, but showed better adsorption for DDTs. It proves that the π-π interaction between benzene rings play a very important role, which is of great significance for the theory study.