Application of Diol column under adsorption and mixed partition–adsorption normal-phase liquid chromatography mode for the separation of purines and pyrimidines

The diol-bonded phase (column LiChrospher 100 Diol) has been studied for the separation of some purines and pyrimidines under normal-phase liquid chromatography (NPLC) conditions. Retention time, column efficiency, and selectivity of column with diol-phase were compared to those of unmodified silica (column LiChrospher SI-60). It was established that under adsorption NPLC mode application of diol-phase can reduce the separation time and a little improve the column efficiency. Significant improvement of the column efficiency for polar solutes is observed if mixed partition–adsorption NPLC mode is used. The investigation has shown that application of diol-phase instead of bare silica is useful not only under adsorption, but also under mixed partition–adsorption mode if the system with specific selectivity is necessary.