| Recently, the research of graphene and graphene oxide has become a hot pot. Onthe one hand the content of the research is to improve the synthesis method ofgraphene, on the other hand is to develop the applications of graphene-basedcomposites. Graphene oxide (GO) can be considered as a precursor for thepreparation of graphene and the method is suitable for mass production of grapheneso that it has also become the focus of the research.In this paper, microwave-assisted method on atmospheric pressure and highpressure for the fast synthesis of graphite oxide is developed. Magnetic reducedgraphene oxide (M-RGO) is successfully synthesized and applied in enriching triazineherbicides of environmental water samples combined with high-performance liquidchromatography-tandem mass spectrometry detection. This method was carried out toachieve a rapid extraction of triazines pollutants from environmental water samples.Firstly, microwave-assisted method with C/KMnO4ratio of1w:6w for thepreparation of GO is described. Reaction time is shortened from12h to30s. Thismethod is easy to operate and GO obtained has a high degree of oxidation. Themicrowave irradiation improves the efficiency of the oxidation within seconds. Incontrast to Hummers’ method, the new method does not generate toxic gas and the temperature is easily controlled. This microwave-assisted synthesis of GO have greatpotential in large-scale production of GO. Then, GO was prepared by microwaveradiation under high pressure at70℃. This method is more facile and reactiontemperature is easily controlled. And we characterized the properties of the grapheneoxide synthesized by the two microwave-assisted methods.Secondly, we successfully synthesize reduced graphene oxide with Fe3O4particles which we call it magnetic reduced graphene oxides（M-RGO）. It has a highsaturation magnetization (70.0emu g1) that made it easier and faster to be separatedunder an external magnetic field compared with the traditional solid phase extraction.Under the scanning electron micrographs, it can be seen that Fe3O4particles arespherical and average particle diameter is about500nm, uniformly dispersed on thegraphene sheet. Furthermore, this material has a good adsorption capacity towardsmolecules containing the benzene ring. The properties of the M-RGO werecharacterized X-ray diffraction etc.Thirdly, magnetic reduced graphene oxide（M-RGO） is used as an effectiveadsorbent for enriching triazine herbicides (Simazine, Atrazine, Desmetryn, Ametryn,Prometryn and Propazine) in environmental water samples combined withHPLC-MS-MS detection. The prepared M-RGO had high adsorption propertiestoward triazines and high magnetic response. Therefore, this method could avoid ofthe time-consuming sample pretreatment procedures compared to the traditional solidphase extraction.70mg M-RGO, the extraction time of10min, the pH7of the watersamples,4mL acetone as desorption solvent are selected as optimum conditions forthe extraction of the triazines. The enrichment factor of the method for the analytes isup to500. A linear response was achieved in the concentration range of0.5-500ng L-1.The magnetic reduced graphene oxide exhibited an ultrasensitive detection of triazineherbicides with a detection limits of0.16-0.52ng L-1under the optimum conditions.The recoveries for the triazines in environmental water samples were in the rangefrom72%to93%. The method has been successfully applied for the determination ofthe triazine herbicides in three kinds of environmental water samples in Changchun city. |
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