基于金属掺杂石墨烯的环境样品中多溴联苯醚及其类似物分析方法的研究

Due to good flame-retardant properties, polybrominated diphenyl ethers (PBDEs) are widely used as additives in many types of consumer goods, such as plastics, electronics, textiles, and construction material. PBDEs pose great risk to the environment and human health because of their high persistence, high toxicity, lipophilic property and ability to get into the environment easily owing to the lack of chemical bonds with the matrix of materials. Due to high bioaccumulation, monitoring the presence of PBDEs in ecological systems at very low concentration levels is becoming more and more important. Graphene, a one-atom thick and two-dimensional carbon nanomaterial, has attracted intense interest for its unusual physical properties and great potential in various applications. Recently, graphene was considered as an excellent adsorbent in analytical sample preparation because of its exceptional properties including large surface area, π-electron-rich structure, as well as good thermal and chemical stability. Theoretical study of binding of metal-doped graphene sheet with dioxin demonstrated that graphene sheet can be effective adsorbents for dioxin moleculars in the presence of calcium atoms. This is due to cooperative formation of sandwich complexes of graphene sheet through the interaction π-Ca-π with the total binding energy of more than 3 eV. Therefore, the aim of the present project is to development of new methods by using metal-doped graphene as an absorbent for preconcentration of trace PBDEs as well as their methoxylated (MeO-) and hydroxylated (OH-) analogs from environmental samples. In this proposal, three experimental protocols based on metal-doped graphene as an sbsorbent in sample preparation were designed for the anlysis of PBDEs from environmental samples. For the first two experiment schemes, metal-doped graphene was used as an absorbent of solid-phase extraction (SPE) and coating of solid-phase microextraction (SPME) with sol-gel method, respectively.GC-MS and LC-MS methods coupling SPE and SPME with metal-doped graphene as an absorbent were developed for the analysis of he analysis of PBDEs. In the third protocol, metal-doped graphene was dispersed to environmental samples, and then metal-doped graphene was collected with certification and detected by MALDI- TOF MS. In this experiment, metal-doped graphene was used as not only absorbent for PBDEs as well as their methoxylated (MeO-) and hydroxylated (OH-) analogs, but also assisted matrix for MALDI-TOF MS that could eliminate interference from traditional matrix in low molecular weight region. In summary, the main aim of this research project is development of some new sensitive methods for the analysis of PBDEs as well as their methoxylated (MeO-) and hydroxylated (OH-) analogs by using metal-doped graphene as absorbent with increased interaction between graphene and analytes in presence of metal atoms.

由于PBDEs具有较高亲脂性，化学性质稳定，可远距离传输，并能通过食物链进行累计放大，在生物体内蓄积产生毒性，该类物质产生的污染问题和对人类健康构成的威胁受到高度关注。因具有生物累计和放大作用，即使微量PBDEs进入环境，也会使处于高营养级的人类受到毒害。所以为保障生态安全和人类健康，必须发展高效灵敏的分析技术。但由于PBDEs样品所处基体复杂、易受环境影响、含量非常低，因此必须加大对该类物质的样品前处理技术研究。石墨烯由于具有超大比表面积，完美杂化结构、大π-π共轭体系和富电子疏水特性，被认为是样品前处理领域中的一颗新星，但由于性质稳定，其应用受到一定限制，元素掺杂被认为是有效改善其物化性质的方式之一。本项目拟通过制备金属掺杂石墨烯并结合固相萃取和固相微萃取等样品前处理技术，建立基于色谱、质谱技术的环境样品中超痕量PBDEs及其类似物的分析方法，为生态环境安全和人类健康提供基础保障。

随着仪器设备的快速发展，样品前处理技术已成为样品分析中最重要的环节之一。近年来，石墨烯由于大的比表面积、富电子的π-π共轭结构、高的热稳定及良好的导电和机械性能，被认为是一种理想的吸附材料。我们通过溶溶凝胶一锅法制备了氧化石墨烯二氧化硅（GO@SiO2）材料，作为分散固相萃取吸附剂，用于富集复杂基质样品中的痕量化合物。由于石墨烯具有超轻的特质，常规的高速离心难以将吸附剂完全回收，为解决这一缺陷，我们制备了磁性氧化石墨烯（GO@Fe3O4）材料，通过简单施一外加磁场即可将吸附剂回收。我们通过高温煅烧三聚氰胺的方式制备了石墨相氮化碳（g-C3N4），以层层组装的方式制备了基于该材料的固相微萃取（SPME）涂层，开发了基于该涂层的顶空固相微萃取-气相色谱（HS-SPME-GC）技术。为了进一步提高萃取效率，我们制备了纳米状石墨相氮化碳和氧化铜（nano-g-C3N4/CuO）复合物用于萃取环境水样和土壤中的6种多环芳（PAHs）烃，结合常规GC技术，检测限可达0.025-0.40 ng/mL。以乌洛托品（六亚甲基四胺）为前驱体，我们通过纳米浇铸法合成了有序的介孔氮化碳（MCN），并设计了一种新型固相萃取方式即柱辅助分散固相萃取（CA-dSPE），实现了对环境水样和牛奶样品中5种磺胺类抗生素的高效、灵敏检测，检测限可达0.02 到0.05 ng/mL，远低于常规液相色谱的检测限。为进一步改善MCN性能，合成了NiCo2O4@MCN复合材料，用于血液中的PAHs和多氯联苯（萘、苊、芴、菲、蒽、芘、4-氯联苯、3,5-二氯联苯、3,4-二氯联苯）的吸附。同时制备了ZnFe2O4 和 GO@ZnFe2O4复合材料作为固相萃取吸附剂。我们通过简单的一锅法制备了单分散介孔二氧化硅纳米材料（MSNs）用于去除环境水样中的染料。进一步合成了氨基修饰的MSN及MSN@MOFs-GO复合材料，结果表明MSN@MOFs-GO对多溴联苯醚（PBDEs）类化合物，如2-溴联苯醚（BDE-1）、3-溴联苯醚（BDE-2）、4,4'-二溴联苯醚（BDE-15）、2,2',4,4'-四溴联苯醚（BDE-47）有明显的吸附效果。综上所述，我们制备了系列石墨烯及其相关纳米材料用于复杂基质样品中的痕量化合物的净化和富集，结合色谱、质谱技术实现对这类物质的高灵敏检测。