低共熔溶剂——新型亲水作用色谱流动相改性剂

低共熔溶剂被用作亲水作用色谱流动相的新型改性剂。选用硅胶柱(150 mm×4.6 mm, 3 μm),以乙腈与低共熔溶剂(氯化胆碱-乙二醇(摩尔比为1:3))的混合溶液为流动相,考察了6个碱基与核苷的色谱分离效果,并讨论了低共熔溶剂在流动相中的比例及温度条件对分离的影响。结果表明,与传统的水相流动相条件相比,在加入低共熔溶剂改性后的流动相条件下,碱基与核苷分离效果得到明显的改善,尤其是胞嘧啶与胞苷能达到完全分离;同时,随着低共熔溶剂在乙腈中浓度的增加,6个碱基与核苷在色谱柱上的保留均有不同程度的减小,其中胞苷的保留减小最为显著;随着柱温的升高,碱基与核苷的保留同样有所减小。本文验证了低共熔溶剂作为亲水作用色谱流动相改性剂的可行性,可在一定程度上解决传统亲水作用色谱分离的困难。

Deep eutectic solvent: a new kind of mobile phase modifier for hydrophilic interaction liquid chromatography

Deep eutectic solvents (DESs) were used as a new kind of mobile phase modifier in hydrophilic interaction liquid chromatography (HILIC). In our experiment, a SiO₂ column (150 mm×4.6 mm, 3 μm) was selected to separate several nucleobases and nucleosides by using the mixed solution of acetonitrile and DES (choline chloride-ethylene glycol (1:3, mol/mol)) as mobile phase. Subsequently, the concentrations of DESs in acetonitrile and the column temperature on the effect of separation were investigated. According to the experimental results, better separation of nucleobases and nucleosides was obtained by using acetonitrile and DESs mixed solution as mobile phase than that using traditional water-based solution. For example, a baseline separation between cytosine and cytidine cannot be achieved by HILIC with water-based mobile phase, however, greater improvement was gained by HILIC with modified DES-acetonitrile mobile phase. Meanwhile, the retention times of nucleobases and nucleosides decreased as the proportion of DESs in acetonitrile increased, the most significant decrease of which was with cytidine. Similar retention behavior took place with the effect of column temperature. Decreased retention times of the analytes were observed as column temperature increased. The experimental results indicated that this new method may solve some separation difficulties in traditional water-based HILIC, which also successfully verify the feasibility of DESs as mobile phase modifiers.