STUDIES OF PH-ZONE REFINING COUNTERCURRENT CHROMATOGRAPHY

一种新的制备色谱技术--pH区带精制CCC 本文介绍 该方法利用分区的差异， 可电离化合物的两种分子种类之间的系数，即， pK（a）以下的疏水质子化形式和亲水质子化形式 去质子化形式高于pK（a）。 在分离具有 在一个实施方案中，在羧基上添加有机酸如三氟乙酸， 样品溶液和/或固定相使化合物质子化 同时通过加入碱， 氢氧化铵使化合物去质子化。 当样品 在该特定条件下洗脱，主要组分形成 稳定的pH区，通过饱和的尖锐边界后面的溶剂 酸梯度区，由加入样品的酸形成 溶液或固定相。 在这个由主要的 组分，次要杂质被有效地排除在正向或 这取决于它们的分配系数。 任何样品增加 除了分离之外，尺寸不会影响该纯化过程 时间成比例地增加。 该方法的性能是 在DNP氨基酸和各种氨基酸的制备分离中证明了 羟基氧杂蒽染料。 本方法可以应用于其他方法。 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.