2‐(4‐Chlorophenyl)succinic acid was successfully enantioseparated by countercurrent chromatography using hydroxypropyl‐β‐cyclodextrin as chiral selector. A two‐phase solvent system composed of n‐hexane‐ethyl acetate‐0.1 mol/L phosphate buffer with pH 2.65 (5:5:10, v/v) was selected. Enantioselective liquid–liquid extraction was used to optimize the enantioseparation conditions. Meanwhile, the influence of injection volume on resolution in countercurrent chromatography was investigated and a linear relationship between the inflection point of injection volume and sample loading was tentatively obtained. The peak resolution will decrease significantly when the injection volume over the inflection point was used. In addition, it could be found that the smaller amount of sample loading, the larger impact of injection volume on resolution could be observed, which might serve as a good reference for the selection of sample volume in enantioseparations by countercurrent chromatography. Under optimized conditions, 20 mg of 2‐(4‐chlorophenyl)succinic acid racemate dissolved in 10 mL of aqueous phase was successfully enantioseparated by countercurrent chromatography. The recovery for both of the enantiomer of (±)‐2‐(4‐chlorophenyl)succinic acid reached within 70–75% with a purity of 99.0%.

中文翻译：

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逆流色谱法拆分2-（4-氯苯基）琥珀酸对映体并研究进样量

使用羟丙基-β-环糊精作为手性选择剂，通过逆流色谱法成功地拆分了2-（4-氯苯基）琥珀酸。由n组成的两相溶剂系统选择了pH 2.65（5：5：10，v / v）的-己烷-乙酸乙酯-0.1 mol / L磷酸盐缓冲液。对映选择性液-液萃取用于优化对映分离条件。同时，研究了进样量对逆流色谱分离度的影响，初步确定了进样量拐点与样品上样量之间的线性关系。当使用超过拐点的进样量时，峰分辨率将大大降低。此外，可以发现，样品加载量越小，进样量对分离度的影响就越大，这可以为通过逆流色谱法选择对映体分离中的样品量提供很好的参考。在优化条件下，通过逆流色谱法成功地将20 mg 2-（4-氯苯基）琥珀酸外消旋物溶于10 mL水相中对映体分离。（±）-2-（4-氯苯基）琥珀酸的两种对映异构体的回收率均在70-75％之内，纯度为99.0％。