CAS Key Laboratory of Chemistry of Northwestern Plant Resources, Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China; University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100039, China.
CAS Key Laboratory of Chemistry of Northwestern Plant Resources, Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.
Talanta. 2020 May 1;211:120743. doi: 10.1016/j.talanta.2020.120743. Epub 2020 Jan 15.
In this work, a novel imidazolium ionic liquid-functionalized poly(quinine)-modified silica stationary phase (Sil-PQn-MIm) was successfully synthesized via surface radical chain transfer and nucleophilic substitution reaction. The modified silica was confirmed by series of characterizations including Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The multi-mode chromatographic performances of the Sil-PQn-MIm column were investigated by anion-exchange mode for separation of aromatic acid samples, hydrophilic interaction mode for separation of nucleosides/nucleobases and sulfanilamides, and reversed-phase mode for separation of alkylbenzenes, benzene and polycyclic aromatic hydrocarbons (PAHs), and the Tanaka test mixtures, respectively. As expected, compared to the Sil-PQn column only with quinine as functional group, the Sil-PQn-MIm column further modified by imidazolium ionic liquid possessed higher separation performance, especially for the separation of nucleosides/nucleobases. The effects including buffer concentration, pH, organic solvent content and column temperature on chromatographic performance were studied, which proved that multiple interactions including electrostatic, hydrophobic and hydrophilic interactions can be simultaneously existed between the stationary phase and the analytes. In addition, reproducibility and efficiency of the Sil-PQn-MIm column were also investigated, the results illustrated that the stationary phase have good enough reproducibility (RSDs 0.15%-0.72%, n = 7) and high efficiency (plates per meter, ~90000 plates/m). In conclusion, the prepared stationary phase with multiple-mode retention capabilities could realize separation for various types of samples by optimizing chromatographic conditions, even for some chiral compounds.
在这项工作中，通过表面自由基链转移和亲核取代反应，成功合成了一种新型的咪唑鎓离子液体功能化聚（奎宁）改性硅胶固定相（Sil-PQn-MIm）。通过一系列的表征，包括傅里叶变换红外光谱（FT-IR）、元素分析（EA）、透射电子显微镜（TEM）和热重分析（TGA），证实了改性硅胶的存在。通过阴离子交换模式分离芳香酸样品、亲水作用模式分离核苷/碱基和磺胺类药物、反相模式分离烷基苯、苯和多环芳烃（PAHs），以及 Tanaka 测试混合物，分别研究了 Sil-PQn-MIm 柱的多模式色谱性能。正如预期的那样，与仅具有奎宁作为功能基团的 Sil-PQn 柱相比，进一步用咪唑鎓离子液体修饰的 Sil-PQn-MIm 柱具有更高的分离性能，特别是对于核苷/碱基的分离。研究了缓冲液浓度、pH 值、有机溶剂含量和柱温对色谱性能的影响，结果表明固定相和分析物之间可以同时存在静电、疏水和亲水相互作用等多种相互作用。此外，还研究了 Sil-PQn-MIm 柱的重现性和效率，结果表明固定相具有足够好的重现性（RSDs 0.15%-0.72%，n=7）和高效率（理论塔板数，约 90000 块/m）。总之，这种具有多模式保留能力的固定相可以通过优化色谱条件实现各种类型样品的分离，甚至可以分离一些手性化合物。
