Department of Chemistry, The Ohio State University, Columbus, OH 43210-1185, USA.
J Chromatogr A. 2011 Sep 2;1218(35):5897-902. doi: 10.1016/j.chroma.2010.12.059. Epub 2010 Dec 22.
The application of enhanced fluidity liquid (EFL) mobile phases to improving isocratic chromatographic separation of nucleosides in hydrophilic interaction liquid chromatography (HILIC) mode is described. The EFL mobile phase was created by adding carbon dioxide to a methanol/buffer solution. Previous work has shown that EFL mobile phases typically increase the efficiency and the speed of the separation. Herein, an increase in resolution with the addition of carbon dioxide is also observed. This increase in resolution was achieved through increased selectivity and retention with minimal change in separation efficiency. The addition of CO₂ to the mobile phase effectively decreases its polarity, thereby promoting retention in HILIC. Conventional organic solvents of similar nonpolar nature cannot be used to achieve similar results because they are not miscible with methanol and water. The separation of nucleosides with methanol/aqueous buffer/CO₂ mobile phases was also compared to that using acetonitrile/buffer mobile phases. A marked decrease in the necessary separation time was noted for methanol/aqueous buffer/CO₂ mobile phases compared to acetonitrile/buffer mobile phases. There was also an unusual reversal in the elution order of uridine and adenosine when CO₂ was included in the mobile phase.
描述了增强流动性液体 (EFL) 流动相在改善亲水作用色谱 (HILIC) 模式下核苷等度色谱分离中的应用。EFL 流动相通过向甲醇/缓冲溶液中添加二氧化碳来制备。以前的工作表明，EFL 流动相通常会提高分离的效率和速度。本文还观察到，随着二氧化碳的添加，分辨率也有所提高。这种分辨率的提高是通过增加选择性和保留性，同时最小化分离效率的变化来实现的。向流动相中添加 CO₂ 可有效降低其极性，从而促进在 HILIC 中的保留。具有相似非极性性质的常规有机溶剂不能用于达到类似的结果，因为它们与甲醇和水不混溶。还比较了甲醇/水缓冲/CO₂ 流动相与乙腈/缓冲流动相分离核苷的情况。与乙腈/缓冲流动相相比，甲醇/水缓冲/CO₂ 流动相所需的分离时间明显缩短。当 CO₂ 包含在流动相中时，尿嘧啶和腺苷的洗脱顺序也出现了异常反转。
