Evaluation of Aqueous and Nonaqueous Binary Solvent Mixtures as Mobile Phase Alternatives to Water–Acetonitrile Mixtures for Hydrophilic Interaction Liquid Chromatography by Molecular Dynamics Simulations
Evaluation of Aqueous and Nonaqueous Binary Solvent Mixtures as Mobile Phase Alternatives to Water–Acetonitrile Mixtures for Hydrophilic Interaction Liquid Chromatography by Molecular Dynamics Simulations
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DOI：
10.1021/jp511111z
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发表时间：
2015-01
影响因子：
3.7
通讯作者：
S. Melnikov;A. Höltzel;A. Seidel-Morgenstern;U. Tallarek
中科院分区：
文献类型：
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作者：
S. Melnikov;A. Höltzel;A. Seidel-Morgenstern;U. Tallarek
水(W)-乙腈(ACN)流动相(MP)和亲水固定相的亲水相互作用液相色谱(HILIC)的保留原理是形成富W层，在直接表面区和扩展表面区分别有刚性和扩散部分。通过分子动力学模拟W-丙酮(Ace)、W-甲醇(MeOH)和MeOH-ACN混合物在亲水二氧化硅表面的吸附，我们评估了它们对水和非水HILIC的MP势。我们分析了溶剂和氢键密度分布、溶剂-表面配位以及局部溶剂取向、迁移率和组成。我们的数据表明，W-Ace混合物的行为与W-ACN混合物的行为非常相似，而W-MeOH混合物不能作为HILIC MP，因为SiO_2表面对W和MeOH的相似亲和力阻止了W-MeOH-ACN混合物的优先吸附，形成了刚性的MeOH层，颠倒了表面的极性，阻止了扩散MeOH层的形成。
The retentive principle of hydrophilic interaction liquid chromatography (HILIC) with a water (W)–acetonitrile (ACN) mobile phase (MP) and a hydrophilic stationary phase is the formation of a W-rich layer with a rigid and diffuse part in the immediate and extended surface region, respectively. Through molecular dynamics simulations of the adsorption of W–acetone (Ace), W–methanol (MeOH), and MeOH–ACN mixtures to a hydrophilic silica surface, we evaluate their MP potential for aqueous and nonaqueous HILIC. We analyze solvent and hydrogen-bond density profiles, solvent–surface coordination, as well as local solvent orientation, mobility, and composition. Our data show that W–Ace mixtures closely mimic the behavior of W–ACN mixtures, whereas W–MeOH mixtures fail as HILIC MP because the similar affinity of the silica surface for W and MeOH prevents preferential adsorption of W. MeOH–ACN mixtures form a rigid MeOH layer that reverses the surface polarity and prohibits formation of a diffuse MeOH layer in the e...