| POPs(persistent organic pollutants, called POPs), refers to a class of synthesized chemicals which can be existed in environment for a long time and accumulate to form a harmful effect on human health though the food chains(webs). The negative effects of POPs on environment and human health have attracted wide attention in the world and lots of scholars from various countries are engaged in solving the problem of contaminate of POPs. Therefore, it has a great significance to develop a rapid, accurate, low cost, sensitive detection method for environmental monitoring and human health protection.In this study, we have successfully fabricated three kinds of metal-organic nanotubes: [Cu3(?3-O)(?-OH)(triazolate)2]+ MONTs(Cu-MONTs), [Yb4(AIP)6(2,2'-bipy)]n(Yb-MOFs) and Fe3O4 @ Co-MONTs. We combined these kinds of new material with different sample pretreatment methods and developed the analysis method for trace level of persistent organic pollutants like PCBs and PAHs in drinking water. Drinking water from different locations were used as real samples and were detected by GC-MS/MS in order to validate the adaptability of methods. At the same time, we discussed the adsorption mechanism and commercial value of these new metal-organic nanotubes. The main research results are as follows:1. [Cu3(?3-O)(?-OH)(triazolate)2]+ MONTs(Cu-MONTs) was fabricated by copper(?) nitrate hydrate(Cu(NO3)2·3H2O) 1,2,4-triazole(Htz), Sodium chloride(NaCl), cyanuric acid(H3CA) and aqua ammonia(NH3?H2O) were added in proportion to an ethanediol-H2 O solution under high temperature and high pressure. After cleaning and drying, the porous adsorbent material was obtained. Then we adopted physical bonding to fix the novel adsorbent on the self-made solid-phase microextraction device. Finally, we developed a kind of SPME with MONTs as absorbent, combined with GC-MS/MS, for detection of seven kinds of PCBs in drinking water. Single factor optimization method was used to optimize the adsorption conditions(adsorption time, stirring rate, ionic strength, pH) and desorption condition(desorption temperature and desorption time) in order to get the optimal experimental conditions. The methodology validation and the analysis of real samples were conducted under the optimal conditions. The experimental results showed that the CuMONTs have a good thermal stability, repetition and good adsorption performance in detection trace PCBs in water.2. [Yb4(AIP)6(2,2?-bipy)]n SPME coating was synthesized by an in situ hydrothermal growth method. Yb(NO3), 2,2'-bipy, H2 AIP and water were firstly stirred at room temperature before the mixture solution was transferred to a 100 mL Teflon-lined reactor. Then, the etched stainless steel wire was immersed into the solution. The reactor was sealed and in an oven under high temperature and high pressure for the synthesis of [Yb4(AIP)6(2,2'-bipy)]n. After cooling to room temperature, golden materials were adhered to the surface of the corroded stainless steel wire. The prepared stainless steel wire and a 5 ?L microsyringe were assembled into a home-made SPME device. The fiber was then conditioned in a GC inlet under a nitrogen atmosphere before extraction. We developed a kind of SPME with new material as absorbent, combined with GC-MS/MS, for detection of sixteen kinds of PAHs in drinking water. Though the orthogonal experiment to optimize the adsorption conditions(adsorption time, adsorption temperature) and desorption condition(desorption temperature and desorption time) in order to get the optimal experimental conditions. We made a comparison between the new MONTs-SPME with the existing commercial coatings and discussed the possible adsorption mechanism though selective experiments. The scanning electron microscopy(SEM) showed that the coating surface has a honeycomb structure that in favor of the target ananlytes adsorption. Besides, there are benzene rings in molecular that can lead ?-? stacking interaction between MONTs and the PAHs. So the novel material showed a good adsorption performance. Compared with the previously reported method, the method based on this material showed a lower detection limit, linear range ranged from 10-1000 ng L-1, meet the requirement for general sample detection. This method has a good repeatability, high enrichment factor and was suitable for the detection of PAHs in drinking water.3. Firstly, nanosized ferroferric oxide(Fe3O4) powders were synthesized by condition of solvent heat. Secondly, the surface Fe3O4 were modified by hydroxylated and alkoxysilanes. In the next step, the alkoxysilane-modified MNPs were connected with 4,4?-biphenyldicarboxylic acid(H2bpdc). H2 bpdc, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide(EDC) and 4-dimethylaminopyridine(DMAP) in proportion were added into 50 mL of APS-modified MNPs acetonitrile solution(2 mg mL-1) and stirred for 20 h. Finally, a mixture of H2bpdc-modified MNPS, Co(CH3COO)2·4H2O, 3,3',5,5'-tetramethyl-4,4'-bipyrazole(H2bpz) reacted under high temperature and high pressure for three days and the paramagnetic Fe3O4 @ Co-MONTs core-shell structure of nanomaterials were obtained. The Fe3O4 @ Co-MONTs yolk-shell microspheres were characterized by scanning electron micrographs(SEM), transmission electron microscopy(TEM), Fourier transform infrared spectra, X-ray diffraction(XRD), and vibrating sample magnetometry. The feasibility of the new material for use as an absorbent was investigated for magnetic solid phase-extraction(MSPE) of polychlorinated biphenyls(PCBs) from environmental water samples. The Plackett-Burman design and Box-Behnken design were used to determine and optimize the extraction parameters influencing the extraction efficiency through response surface methodology, respectively. These results demonstrated that Fe3O4 @ Co-MONTs is a promising adsorbent material for the MSPE of PCBs at trace levels from drinking water samples. |
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