Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
Department of Applied Chemistry and Biochemistry, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan; National Institute of Technology, Okinawa College, 905, Henoko, Okinawa 905-2192, Japan.
J Chromatogr A. 2023 Mar 29;1693:463885. doi: 10.1016/j.chroma.2023.463885. Epub 2023 Feb 21.
We described two novel zwitterionic polymer-terminated porous silica stationary phases containing the same pyridinium cation and anions of different side chains (carboxylate and phosphonate groups) for use in hydrophilic interaction liquid chromatography (HILIC). These two novel columns were prepared by polymerizing 4-vinylpyridine and grafting it onto a silica surface, followed by quaternization reaction with 3-bromopropionic acid (Sil-VPC) and (3-bromopropyl) phosphonic acid (Sil-VPP), which possess positively charged pyridinium groups, and negatively charged carboxylate and phosphonate groups, respectively. The products obtained were verified through relevant characterization techniques such as elemental analysis, Fourier-transform infrared spectroscopy, thermogravimetric analysis, Zeta potential analysis, and Brunauer-Emmett-Teller analysis. The retention properties and mechanisms of different types of compounds (neutral, cationic, and anionic) on the two zwitterionic-modified silica stationary phases were studied by varying the buffer salt concentration and pH of the eluent. The separation of phenol and aromatic acids, disubstituted benzene isomers, sulfonamide drugs, as well as nucleosides/nucleobases were investigated on the two packed novel columns and a commercial zwitterionic column in identical HILIC mode, ensuring a thorough comparison between both novel columns and with a commercial standard. The results illustrated that various compounds could be separated up to various efficiencies based on the mechanism of hydrophilic interaction-based retention between the solutes and the two zwitterionic polymer stationary phases. The Sil-VPP column demonstrated the best separation performance out of the three, as well as flexible selectivity and excellent resolution. Both novel columns exhibited excellent stability and chromatographic repeatability for the separation of seven nucleosides and bases.
我们描述了两种新型两性离子聚合物封端的多孔硅胶固定相，它们含有相同的吡啶阳离子和不同侧链阴离子（羧酸根和膦酸根），用于亲水相互作用液相色谱（HILIC）。这两种新型色谱柱是通过聚合 4-乙烯基吡啶并接枝到硅胶表面，然后用 3-溴丙酸（Sil-VPC）和（3-溴丙基）膦酸（Sil-VPP）进行季铵化反应制备的，它们分别带有带正电荷的吡啶鎓基团和带负电荷的羧酸根和膦酸根。通过元素分析、傅里叶变换红外光谱、热重分析、Zeta 电位分析和 Brunauer-Emmett-Teller 分析等相关表征技术验证了产物的结构。通过改变洗脱液的缓冲盐浓度和 pH 值，研究了不同类型化合物（中性、阳离子和阴离子）在两种两性离子改性硅胶固定相上的保留特性和机理。在相同的 HILIC 模式下，对两种填充新型色谱柱和一种商业两性离子色谱柱进行了苯酚和芳香酸、二取代苯异构体、磺胺类药物以及核苷/碱基的分离，确保了两种新型色谱柱与商业标准之间的全面比较。结果表明，根据溶质与两种两性离子聚合物固定相之间基于亲水相互作用的保留机理，各种化合物可以达到不同的分离效率。Sil-VPP 柱在三种柱中表现出最佳的分离性能，具有灵活的选择性和优异的分辨率。两种新型色谱柱在分离七种核苷和碱基时均表现出出色的稳定性和色谱重复性。
