Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Department of Applied Physics and Photonics, Brussels Photonics (B-PHOT), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
J Chromatogr A. 2019 Jun 21;1595:58-65. doi: 10.1016/j.chroma.2019.02.035. Epub 2019 Feb 15.
We report on the ability to change the layer properties of porous layered radially elongated pillar (PLREP) array columns and its relevance to the separation efficiency. The adjustment of the preparation condition resulted in the formation of a 1.2-fold thicker layer than the layer produced in the preceding study. The mesoporosity of the layer was controlled by changing the hydrothermal treatment temperature from 105 °C to 80 °C. Chromatographic characterization was performed on a commercial nano-LC system using the octadecylsilylated PLREP columns having the aforementioned characteristics, i.e. (1) different layer thickness (d = 180-220 nm) and (2) different mesoporosity (d = 7.6-11.2 nm, Pore volume (V) = 0.733‒0.838 cc/g and Surface area (SA) = 364‒611 m/g). For isocratic separations of an alkylphenone mixture, the change in both the layer thickness and the mesoporosity caused no significant difference in the column efficiency, while the thicker layer and the reduction of mesopore size resulted in a 1.3-fold increase and a 1.4-fold increase in the retention capacity, respectively. Based on the result of the examination using scanning electron microscopy and argon physisorption technique, the formar enhancement was in agreement with the increase in the layer thickness, and the latter one was attributed to the larger surface area. When applying a column with 16.5 cm long to gradient separations, the combination of the thicker layer and the smaller mesopores provided the peak capacity of 365 for the alkylphenone mixture at a 180 min gradient, while the combination of the thinner layer and the larger mesopores provided the peak capacity of 315. For peptide separations, it appeared that the thicker layer was still favorable, however, the lager mesopores were more advantageous for MWs of larger than 1000, providing a conditional peak capacity of 245 for a commercially available peptide mixture because of less content of small pores which hinder the diffusion of large molecules in pores in the layer.
我们报告了改变多孔层状径向拉长柱（PLREP）阵列柱的层性质的能力及其与分离效率的相关性。通过调整制备条件，形成了比前一研究中形成的层厚 1.2 倍的层。通过将水热处理温度从 105°C 改变为 80°C 来控制层的中孔性。使用具有上述特性的十八烷基硅烷化 PLREP 柱在商业纳升 LC 系统上进行色谱特性分析，即（1）不同的层厚（d=180-220nm）和（2）不同的中孔性（d=7.6-11.2nm，孔体积（V）=0.733-0.838cc/g 和表面积（SA）=364-611m/g）。对于烷基苯酮混合物的等度分离，层厚和中孔性的变化对柱效率没有显著影响，而较厚的层和中孔尺寸的减小分别导致保留能力增加了 1.3 倍和 1.4 倍。根据扫描电子显微镜和氩气物理吸附技术的检查结果，前者的增强与层厚度的增加一致，而后者归因于更大的表面积。当将 16.5cm 长的柱子应用于梯度分离时，较厚的层和较小的中孔的组合在 180 分钟的梯度分离中为烷基苯酮混合物提供了 365 的峰容量，而较薄的层和较大的中孔的组合提供了 315 的峰容量。对于肽分离，似乎较厚的层仍然有利，但是较大的中孔对于分子量大于 1000 的肽更有利，为市售的肽混合物提供了 245 的条件峰容量，因为层中的小孔含量较少，这会阻碍大分子在孔中的扩散。
