多壁碳纳米管键合硅胶固定相的保留机理研究  

Study of Retention Mechanism of Multi-walled Carbon Nanotubes Coated Silica Microspheres as Stationary Phase

作　　者：唐亚楠[1,2] 孙小明[2] 邸多隆[1,2] 

机构地区：[1]甘肃中医学院药学系甘肃省高校中(藏)药化学与质量研究省级重点实验室,甘肃兰州730000 [2]中国科学院兰州化学物理研究所中国科学院西北特色植物资源化学重点实验室和甘肃省天然药物重点实验室,甘肃兰州730000

出　　处：《分析测试学报》2015年第1期1-8,共8页Journal of Instrumental Analysis

基　　金：国家自然科学基金资助项目(21205126)

摘　　要：制备了3种不同键合量的多壁碳纳米管键合硅胶固定相。以芳香族化合物为目标分析物,甲醇-水为流动相,分别考察了其在不同流动相比例、流速、柱温条件下,酸性、中性、碱性化合物的色谱保留行为,并通过计算分离过程中焓变、熵变和吉布斯自由能等热力学参数,探讨了色谱柱的保留机理。结果表明,碳纳米管键合硅胶与未键合的硅胶固定相分离对氨基苯磺酸和尿嘧啶时,因碳纳米管的加入增强了其疏水作用,保留机理与反相色谱柱相似。而分离中性化合物时,因加入的碳纳米管引入π-π作用,增强了对化合物的保留,有效地提高了色谱柱的柱效。碳纳米管的加入使溶质分子在固定相上的保留增强,溶质分子从杂乱无序排列转为有序排列,且溶质分子在不同碳纳米管键合量的色谱柱上的保留并非由单一机理支配,而是由多种作用相互协同的结果,这使碳纳米管键合硅胶固定相在分离和固相萃取领域展现出良好的应用前景。Three kinds of chromatographic columns were prepared by coating multi walled carbon nanotubes on the silica microspheres.To investigate retention behaviors of acidic,neutral and alkaline compounds,several kinds of aromatic compounds were used as target analytes.The separation conditions,such as ratios of methanol to water in mobile phase,column temperatures and flow rates were also investigated.In addition,the thermomechanical behaviors were discussed by calculating the thermodynamic parameters of enthalpy change,entropy change and gibbs free energy change in the process of separation.The result showed that the hydrophobicity of stationary phases was enhanced by coating carbon nanotubes.The retention mechanism was similar to reversed phase chromatographic column during the separation of sulfanilic acid and uracil.For neutral compound,the retention value and column efficiency were improved effectively because of π-π conjugate effects of carbon nanotubes.The arrangements of analytes changed from disordered to orderd,because of the addition of carbon nanotubes enhanced the retention of analytes on stationary phase.Besides,the retention mechanisms of analytes on different chromatographic columns are not dominated by one single retention mechanism,but by various mechanisms in a coordinated way.These results suggest the importance and great potential of multi-walled carbon nanotubes coated silica microspheres as stationary phase in the applications of separation and solid-phase extraction.

关 键 词：多壁碳纳米管 硅胶 固定相 保留机理 

分 类 号：O657.72[理学—分析化学] O625[理学—化学]