大黄素键合硅胶柱高效液相色谱法分离酸性芳香族化合物

Separation of Acidic Aromatic Compounds on an Emodin-bonded Silica Gel Chromatographic Column by HPLC

本文以传统的C18和苯基柱为参比,将自制的大黄素键合硅胶液相色谱柱(ESP柱)应用于14种芳香族酸性化合物,以及实际样品复方水杨酸搽剂的高效液相色谱(HPLC)分离分析,考察了流动相pH值和甲醇含量对ESP柱分离芳香族酸性化合物的影响,研究ESP柱对酸性化合物的选择性和分离机理。结果表明,在甲醇-0.02mol·L-1KH2PO4(pH=2.5)流动相体系中,三组酸性物质混合样品和实际样品中四种主要成分在ESP柱上实现基线分离。与C18和苯基柱相比,在相同条件下,ESP柱对这类酸性化合物具有较好的选择性,部分芳香酸类化合物的洗脱顺序与C18和苯基柱具有显著差异,其中6种溶质在ESP柱上的保留明显强于C18柱和苯基柱,这说明不同保留机理的存在。研究表明ESP与酸性化合物之间除了存在疏水作用外,p-π和π-π作用、氢键作用、电荷转移作用、偶极-偶极作用对分离也有贡献。与C18和苯基柱相比,丰富的作用机制使ESP柱对极性、电离性物质如对甲苯磺酸、对氨基苯磺酸、苦杏仁酸、间苯二甲酸、对苯二甲酸和水杨酸等具有较强的保留,且分离度有一定的改善。

A self-made emodin-bonded silica gel chromatographic column（ESP）was used for the separation of fourteen acidic aromatic compounds and the sample of compound salicylic acid liniment by HPLC.The chromatographic behavior of the solutes was studied in comparison with conventional C18 and phenyl column.The influence of mobile phase variables such as methanol content and pH on the retention behavior was investigated.And,the chromatographic separation selectivity and retention mechanism of these solutes on ESP column were also discussed.The results showed that baseline separation of three series of aromatic acids mixed standards and four main components in the sample was achieved on ESP using different content of methanol-0.02mol·L^-1KH2PO4（pH=2.5）as mobile phases.Compared with C18 and phenyl column,ESP showed better separation selectivity.Different elution orders were observed for these acidic solutes with different substituents and six solutes exhibited stronger affinities to ESP under the same chromatographic condition.The chromatographic results indicated that synergistic interactions existed on ESP,such as hydrophobic interaction,p-π andπ-πinteraction,hydrogen bonding interaction,the charge transfer interaction,and dipole-dipole interaction.The polar and ionized analytes,such as p-methylbenzenesulfonic acid,p-aminobenzenesulfonic acid,mandelic acid,mphthalic acid,p-phthalic acid and salicylic acid showed stronger affinities to ESP and the resolution had some improvement because of various synergistic mechanism.