Ferulic acid stereoisomers are the most abundant phenolic acids in cereal bran. However, it is challenging to separate them because of the similar structures and properties. In this study, a preparative separation method of ferulic acid stereoisomers from the crude extract of wheat bran was successfully developed. The method contained a two-step separation, the traditional counter-current chromatography (CCC, hexane: ethyl acetate: methanol: water = 2:5:2:4) was followed with a pH-zone-refining CCC (hexane: ethyl acetate: acetonitrile: water = 2:5:2:2, 10 mmol L⁻¹ trifluoroacetic acid in organic stationary phase and 10 mmol L⁻¹ ammonia in aqueous mobile phase). Trans-ferulic acid and cis-ferulic acid with HPLC high purity over than 99% and 98% can be yielded in large-scale separation. Moreover, it is found that different proton affinity, deprotonation ability and interaction site of hydrogen bond result in distinct partition behavior of stereoisomers, which is illustrated by quantitative analysis of molecular surface. This contributes to our in-depth understanding of the separation mechanism toward pH-zone refining CCC. The developed method can be applied in the exploitation of ferulic acids and related phenolic acids from other resources.

阿魏酸立体异构体是谷类麸皮中含量最丰富的酚酸。然而，由于相似的结构和性质，将它们分开是具有挑战性的。本研究成功开发了一种从麦麸粗提物中分离出阿魏酸立体异构体的制备方法。该方法包括两步分离，传统的逆流色谱法（CCC，己烷：乙酸乙酯：甲醇：水= 2：5：2：4）之后是pH区域精制的CCC（己烷：乙酸乙酯） ：乙腈：水＝ 2：5：2：2，在有机固定相中为10 mmol L ^-1三氟乙酸，在水相流动相中为10 mmol L ^-1氨。反式阿魏酸和顺式大规模分离可得到HPLC纯度高于99％和98％的β-阿魏酸。此外，发现不同的质子亲和力，去质子化能力和氢键的相互作用位点导致立体异构体的明显分配行为，这通过分子表面的定量分析来说明。这有助于我们深入了解pH区域精制CCC的分离机理。该方法可用于其他资源中阿魏酸和相关酚酸的开采。