Application Of Carbon-Based Functional Materials In The Complex Matrix Sample Pretreatment

Graphene, a novel class of carbon nanostructures, possessing an ultrahigh specific surface area, has great potentials for using as an adsorbent. In the paper, samples were extracted by graphene packed SPE cartridges, and eluted by ionic liquid assisted methanol solutions and dichloromethane solutions. Then an ultra performance liquid chromatography tandem mass spectrometry combined with graphene-SPE method was developed for the determination of five aryl pyrazole compounds residues in water samples. The linearity of the method was in the range from0.1to100μg/mL, with the correlation coefficients (r) ranging from0.9990to0.9999. The recoveries of the aryl pyrazole compounds from water samples were in the range between87.7%and99.1%, the RSD varied from1.2%to4.4%.Secondly, an ultrasound-assisted magnetic SPE procedure with an Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed to determinate seven polychlorinated biphenyls (PCBs; PCB-28, PCB-52, PCB-101, PCB-118, PCB-138, PCB-153and PCB-180) simultaneously in environmental water samples, in combination with gas chromatography-tandem mass spectrometry. Several factors related to magnetic solid-phase extraction efficiencies, such as the superparamagnetic intensity and amount of adsorbent, extracting time, sample pH, and desorption conditions were investigated. The extraction achieved the maximum with only20s, the enrichment factors for the analytes ranged between1719and2460. The LODs and LOQs for7PCBs were in the range of0.03～0.12ng/L and0.08-0.41ng/L, respectively. And an excellent linearity was observed, with the correlation coefficients ranging from0.9988to0.9996. The developed method was successfully applied in the analysis of7PCBs in tap water, lake water and river water. The mean recoveries at three spiked levels were84.9～108.5%, the RSD were less than6.5%. With convenient magnetic separation, the synthesized magnetic adsorbent could be recycled more than10runs.Finally, a magnetic solid-phase extraction based on chloromethylated polystyrene-coated magnetic nanoparticles as the magnetic adsorbent has been developed for the simultaneous determination of eight phthalate esters (BMPP, DPP, DHXP, BBP, DBEP, DCHP, DNOP and DNP) simultaneously in beverage samples, in combination with gas chromatography-tandem mass spectrometry. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, salt concentration, and desorption conditions were investigated. The enrichment factors of the method for the8analytes were over2482. A good linearity was observed, with the correlation coefficients ranging from0.9980to0.9998. The LODs and LOQs for8PAEs were in the range of0.20～2.90ng/L and0.67-9.67ng/L, respectively. The developed method was successfully applied in the analysis of8PAEs in beverage samples. The mean recoveries at3spiked levels were75.8%～117.7%, the RSD were less than11.7%.