Layered double hydroxides (LDHs) have gained much attention in absorption and extraction fields due to their special structure and properties like high porosity, large surface area and excellent anion exchange capacity. However, LDHs are rarely used in capillary electrochromatography (CEC) by date due to the lack of appropriate immobilization method. In this work, by utilizing the unique coordination bonding between metal ions on LDHs and catechol groups on polydopamine layer, a polydopamine modification method was developed for in situ immobilization of LDHs on the inner surface of fused silica capillary. The formation of CoAl-LDHs on polydopamine-immobilized capillary has been characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The CoAl-LDHs-modified open-tubular capillary exhibited good separation performance towards neutral compounds by cation-π interaction and hydrophobic interaction. More interestingly, by virtue of the coordination interaction between metal ions on LDHs layer and phenolic hydroxyl groups, the LDHs-modified capillary has shown good separation efficiency towards various phenolic compounds. Repeatability of the column was studied, with the relative standard deviations for intra-day, inter-day and column-to-column lower than 4.3%.

层状双氢氧化物（LDHs）由于其特殊的结构和特性（如高孔隙率，大表面积和出色的阴离子交换容量）而在吸收和萃取领域引起了广泛关注。但是，由于缺乏适当的固定方法，LDH迄今为止很少用于毛细管电色谱法（CEC）。在这项工作中，通过利用LDHs上的金属离子与聚多巴胺层上的邻苯二酚基团之间的独特配位键，开发了一种用于原位的聚多巴胺改性方法将LDHs固定在熔融石英毛细管的内表面上。通过扫描电子显微镜，傅立叶变换红外光谱和X射线衍射对在聚多巴胺固定的毛细管上形成CoAl-LDHs进行了表征。CoAl-LDHs修饰的开孔毛细管通过阳离子-π相互作用和疏水相互作用对中性化合物表现出良好的分离性能。更有趣的是，由于LDHs层上的金属离子与酚羟基之间的配位相互作用，LDHs改性的毛细管对各种酚类化合物显示出良好的分离效率。研究了色谱柱的可重复性，其中日内，日间和色谱柱至色谱柱的相对标准偏差低于4.3％。