Applying Magnetic Nanomaterials To The Analysis Of Trace Organic Pollutants In Water

Firstly, a magnetic solid-phase extraction based on chloromethylated polystyrene-coated magnetic nanoparticles as the magnetic adsorbent has been developed for the simultaneous determination of seven polychlorinated biphenyls(PCBs; PCB28, PCB52, PCB101, PCB118, PCB138, PCB153 and PCB180) in water samples, in combination with gas chromatography-tandem mass spectrometry. Several factors related to magnetic solid-phase extraction efficiencies, such as the amount of adsorbent, extracting time, salt concentration, and desorption conditions were investigated. Under the optimized conditions, the LODs and LOQs for seven PCBs were in the range of 0.03-0.13 ng/L and 0.08-0.43ng/L, respectively. And an excellent linearity was observed, with the correlation coefficients ranging from 0.9990 to 0.9998. The developed method was successfully applied in the analysis of seven PCBs in three environment samples. The mean recoveries at three spiked levels were 80.4%-108.2%, the RSD were less than 6.9%.Secondly, ionic liquid coated magnetic nanoparticles(Fe3O4/PS[im-Cn]Cl n=1, 4, 6, 10) have been prepared by covalent immobilization, the as-synthesized magnetic nanoparticles has been used as adsorbent for the extraction of five sulfonamides(STZ、SMZ、SME、SDX 、SIZ) from environmental water samples, in combination with HPLC-PDA. Several significant factors that affect the extraction efficiency, such as the kind of magnetic nanoparticle, the amount of magnetic nanoparticles, extraction time, solution pH, the kind and volume of eluent were investigated. Under the optimized conditions, the LODs for five SAs were in the range of 0.10-0.19 μg/L. And an excellent linearity was observed in the range of 0.6-120 μg/L for five SAs, with the correlation coefficients ranging from 0.9996 to 0.9997. With the strong adsorption, 100 mL water could be treated by only 5 mg magnetic adsorbent.Finally, an ultrasound-assisted magnetic SPE procedure with an Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed to determine three polychlorinated biphenyls(PCBs; PCB28, PCB52, PCB101) simultaneously in environmental water samples, in combination with thermal desorption-gas chromatography-tandem mass spectrometry. Several factors related to recoveries,such as the initial temperature and splitless time of the CIS, and the desorption temperature, time and flow of the TDU. Under the optimized conditions, the LODs for three PCBs were in the range of 1.5-2.3 ng/L. And an excellent linearity was observed, with the correlation coefficients ranging from 0.9957-0.9986. This is a new thought for magnetic solid-phase extraction.