Screening strategies for achiral supercritical fluid chromatography employing hydrophilic interaction liquid chromatography-like parameters
Screening strategies for achiral supercritical fluid chromatography employing hydrophilic interaction liquid chromatography-like parameters
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DOI：
10.1016/j.chroma.2011.12.089
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发表时间：
2012-03-16
影响因子：
4.1
通讯作者：
Seest, E.
中科院分区：
文献类型：
--
作者：
Ashraf-Khorassani, M.;Taylor, L. T.;Seest, E.
对两个主要供应商的5 μ m裸二氧化硅用于极性分析物的非手性超临界流体色谱进行了全面评价。柱的尺寸相同，并且为每种改性剂-混合物组合保留一个原始柱。制备了三种混合物，并通过甲醇改性的CO2梯度进行色谱分离，其中加入5%（w/w）水作为中性添加剂。混合物（A）同时使用三氟乙酸和水作为添加剂。混合物（B）使用异丙胺和水;而混合物（C）使用乙酸铵和水作为添加剂或仅使用水。无论混合物组分和移动的相组成如何，在15天内的5个分析日观察到具有优异上级选择性和优异峰分离度的重复分离。随后从每个移动的相中除去水（即主要添加剂）导致早期洗脱组分的选择性降低，但在仅使用次要添加剂的5天测试期内，后期洗脱峰的峰分辨率优异。在移动的相中重新引入5%的水（在使不含水的裸硅胶柱静置30天后），在约5次进样后缓慢产生初始分离。提出了一种亲水相互作用液相色谱（HILIC）的SFC机制，即分析物之间的分区吸附在二氧化硅和水的移动的相。随后通过用先前与三种模型化合物混合物一起使用的四种移动的相中的每一种单次注射十种药物样化合物来证明这种使用裸二氧化硅的实验方法的一般效用。在每种情况下，尽管保留时间随所用添加剂而变化，但对于每种药物样化合物均观察到尖峰，而与添加剂无关。(C)2012 Elsevier B. V.保留所有权利。
A thorough evaluation of 5 mu m bare silica from two major vendors for achiral supercritical fluid chromatography of polar analytes has been carried out. Columns were the same dimension, and a virgin column was reserved for each modifier-mixture combination. Three mixtures were prepared and chromatographically separated via a gradient of methanol-modified CO2 that incorporated 5% (w/w) water as a neutral additive. Mixture (A) invoked both trifluoroacetic acid and water as additives. Mixture (B) utilized isopropyl amine and water; while mixture (C) employed either ammonium acetate and water as additives or only water. Regardless of the mixture components and mobile phase composition, duplicate separations with superior selectivity and excellent peak resolution were observed on five analysis days over a 15-day period. Subsequent removal of water (i.e. primary additive) from each of the mobile phases led to lower selectivity for early eluting components but excellent peak resolution prevailed for later eluting peaks during a later 5-day testing period with only the secondary additive. The re-introduction of 5% water into the mobile phase (after allowing the bare silica columns that were used with no water to sit for 30 days) slowly yielded the original separation after approximately five injections. A hydrophilic interaction liquid chromatography (HILIC)-like mechanism for SFC whereby analyte partitions between water absorbed on the silica and water in the mobile phase is proposed. The general utility of this experimental approach with bare silica was subsequently demonstrated by single injection of ten drug-like compounds with each of the four mobile phases that previously were utilized with the three model compound mixtures. In each case, sharp peaks were observed for each drug-like compound regardless of the additive although retention times varied with the additive employed. (C) 2012 Elsevier B.V. All rights reserved.