In this work, the synthesis, characterization and chromatographic performance of a silica material chemically bonded with a liquid crystal based on terminal citronellol for HPLC separation were investigated. This bonded liquid crystal stationary phase denoted as LC-LCC8 resulted from the grafting of a mesogenic carboxylic acid, 3′-((3,7-dimethyloct-6-en-1-y1)oxy)-[1,1′-biphenyl]-4-carboxylic acid (LCC8), on 4-(1,1-dimethyldisiloxanyl)butan-1-amine. LCC8 was previously synthesized and characterized by proton NMR, and a nematic mesophase at 127 °C was confirmed by differential scanning calorimetry and microscopy. The resulting stationary phase LC-LCC8 was characterized by using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and elemental analysis. The granulometric distribution was evaluated by scanning electron microscopy (SEM) before and after grafting. An analytical column (150 mm × 2.1 mm × 5 µm) was packed with the stationary phase for the chromatographic study. The chromatographic behaviour of the stationary phase was first characterized using the Tanaka test, exhibiting an exceptionally high shape selectivity (αT/O = 3.9). In normal-phase mode, using a 92/8 cyclohexane/tetrahydrofuran (THF) (v/v) mixture as the mobile phase, the isomeric mixture (Z and E) of crotamiton was well separated. In reversed-phase mode, good selectivity was observed towards organic pollutants [polycyclic aromatic hydrocarbons (PAHs)] and pharmaceutical compounds (xanthines, steroids and antihistamines). The new bonded phase showed satisfactory results both in normal- and reversed-phases modes except in terms of peak shape. The temperature effect on the selectivity and resolution of LC-LCC8 was estimated by injecting different isomers at various temperatures ranging from 293 to 333 K, demonstrating an improved resolution of solutes at high temperatures, which was probably due to a change in orientation order of the grafted ligands.

中文翻译：

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用于正相和反相 HPLC 模式的原始中间基香茅醇固定相：特性和应用

在这项工作中，研究了基于末端香茅醇与液晶化学键合的硅胶材料的合成、表征和色谱性能，用于 HPLC 分离。这种键合液晶固定相表示为 LC-LCC8 由介晶羧酸 3'-((3,7-二甲基辛基-6-en-1-y1)oxy)-[1,1'-联苯的接枝产生]-4-羧酸(LCC8)，在4-(1,1-二甲基二硅氧烷基)丁-1-胺上。LCC8 先前已合成并通过质子 NMR 进行表征，并通过差示扫描量热法和显微镜确认了 127 °C 的向列中间相。通过使用漫反射红外傅立叶变换 (DRIFT) 光谱和元素分析来表征所得固定相 LC-LCC8。在接枝前后通过扫描电子显微镜（SEM）评估粒度分布。分析柱 (150 mm × 2.1 mm × 5 µm) 中装有用于色谱研究的固定相。固定相的色谱行为首先使用 Tanaka 测试进行表征，表现出异常高的形状选择性 (αT/O = 3.9)。在正相模式下，使用 92/8 环己烷/四氢呋喃 (THF) (v/v) 混合物作为流动相，可很好地分离克罗米通的异构体混合物（Z 和 E）。在反相模式下，观察到对有机污染物 [多环芳烃 (PAH)] 和药物化合物（黄嘌呤、类固醇和抗组胺药）具有良好的选择性。除了峰形之外，新的键合相在正相和反相模式下都显示出令人满意的结果。通过在 293 到 333 K 的不同温度下注入不同的异构体来估计温度对 LC-LCC8 选择性和分辨率的影响，表明高温下溶质的分辨率提高，这可能是由于接枝配体。