Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran.
Department of Analytical Chemistry, Faculty of Chemistry, University of Kashan, Kashan, Iran.
J Chromatogr A. 2018 Sep 14;1567:55-63. doi: 10.1016/j.chroma.2018.06.059. Epub 2018 Jun 25.
A two-step ZnO nanoparticle-directed method has been implemented to prepare polymer monolith/zeolitic imidazolate framework (ZIF) solid-phase microextraction (SPME) fiber coatings with hierarchical micro-meso-macroporosity. The polymer/ZIF monolith was prepared on the surface of a stainless steel wire from a polymerization mixture containing dispersed ZnO nanoparticles. The embedded ZnO nanoparticles in the precursor polymer monolith coating were converted on-fiber to submicrometric porous crystals of the prototypical ZIF-8, based on the coordination of Zn(II) with 2-methylimidazole. The polymer/ZIF monolith coating was applied to the headspace SPME of benzene, toluene, ethylbenzene, and xylenes (BTEX) from water samples, followed by gas chromatography-flame ionization detection (GC-FID). Hierarchically porous polymer/ZIF monolithic coatings showed a superior performance for BTEX extraction in comparison to coatings based on pure macroporous organic polymer monoliths, silicone glue/ZIF-8 coatings or commercial PDMS coatings. Experimental parameters such as desorption temperature, desorption time, salt concentration, temperature effect, equilibrium time and extraction time were investigated. Under the selected experimental conditions, limits of detection of 0.02-0.11 μg L, linear ranges of 0.2-200 μg L, relative standard deviations of 4.3-8.2%, and a fiber-to-fiber reproducibility of 8.9-9.8% (n = 3) were obtained. Recoveries higher than 88% were obtained for BTEX analysis in tap water, wastewater and landfill leachates.
已实施两步 ZnO 纳米粒子导向法来制备具有分级微-介-大孔的聚合物整体柱/沸石咪唑酯骨架（ZIF）固相微萃取（SPME）纤维涂层。聚合物/ZIF 整体柱是从含有分散 ZnO 纳米粒子的聚合混合物在不锈钢丝表面制备的。在纤维上，前驱体聚合物整体柱涂层中的嵌入 ZnO 纳米粒子基于 Zn(II)与 2-甲基咪唑的配位，转化为原型 ZIF-8 的亚微米多孔晶体。聚合物/ZIF 整体柱涂层用于从水样中顶空 SPME 苯、甲苯、乙苯和二甲苯（BTEX），随后进行气相色谱-火焰离子化检测（GC-FID）。与纯大孔有机聚合物整体柱、硅胶胶/ZIF-8 涂层或商业 PDMS 涂层相比，具有分级多孔结构的聚合物/ZIF 整体柱涂层对 BTEX 的萃取性能更优。研究了实验参数，如解吸温度、解吸时间、盐浓度、温度效应、平衡时间和萃取时间。在选定的实验条件下，检测限为 0.02-0.11μg/L，线性范围为 0.2-200μg/L，相对标准偏差为 4.3-8.2%，纤维间重现性为 8.9-9.8%（n=3）。在自来水中、废水中和垃圾渗滤液中对 BTEX 进行分析时，回收率高于 88%。
