STUDIES OF PH-ZONE REFINING COUNTERCURRENT CHROMATOGRAPHY

一种名为“pH区精制CCC”的新制备层析技术 介绍了它的基本原理和特点。该方法利用了分区中的差异 可电离化合物的两个分子物种之间的系数，即， PK(A)以下的疏水质子化形式和亲水性 PK(A)以上的去质子化形式。在化合物的分离中使用一个 羧基，一种有机酸，如三氟乙酸，添加到 使化合物质子化的样品溶液和/或固定相 而通过添加如下碱来提高流动相的pH 氢氧化铵使化合物去质子化。当样本是 在这种特殊条件下洗脱，主要成分(S)形成 稳定的pH值区域通过饱和在尖锐的边缘后面的溶剂 酸梯度带，由加入到样品中的酸形成 溶液或固定相。在这一酸碱度范围内， 组件中，少量杂质被有效地向前或向外排除 向后取决于它们的分配系数。样本的任何增加 大小不影响此纯化过程，但分离 时间是按比例增加的。该方法的性能是 在DNP氨基酸和各种氨基酸的制备分离中得到展示 羟基黄原烯染料。本方法可以应用于其他 包括许多有机酸和碱的化合物。

A new preparative chromatographic technique called "pH-zone refining CCC" is introduced. The method utilizes the difference in partition coefficient between two molecular species of an ionizable compound, i.e., the hydrophobic protonated form below the pK(a) and hydrophilic deprotonated form above the pK(a). In the separation of compounds with a carboxylic group, an organic acid such as trifluoroacetic acid is added to the sample solution and/or the stationary phase to protonate the compounds while the pH of the mobile phase was raised by adding a base such as ammonium hydroxide to deprotonate the compounds. When the sample is eluted under this particular condition, the major component(s) forms a stable pH zone by saturating the solvent behind the sharp border of the acid gradient zone, which is formed by the acid added to the sample solution or the stationary phase. Within this pH-zone formed by the major component, minor impurities are efficiently excluded either forward or backward depending on their partition coefficient. Any increase in sample size does not affect this purification process except that the separation time is proportionally increased. The capability of the method was demonstrated in the preparative separation of DNP amino acids and various hydroxyxanthene dyes. The present method may be applied to other compounds including many organic acids and bases.