CHROMATOGRAPHIC CHARACTERISTICS OF NUCLEIC-ACID COMPONENTS ON VINYL ALCOHOL COPOLYMER GEL COLUMNS

The chromatographic characteristics of nucleic acid components on an Asahi-pak GS-320 vinyl alcohol copolymer gel column were investigated in comparison with those on an ODS column. On both columns the order of elution within each class (nucleotide, nucleoside or nucleic acid base) was generally pyrimidine compounds followed by purine compounds, the only exception being the late elution of thymine from the GS-320 and, particularly, from the ODS column. Between the three classes of nucleic acid components, the two columns exhibited different elution orders. On the GS-320 column, the order was consistently nucleotide, nucleoside and base, i.e., in order of increasing water solubility, with a consistent correlation between capacity factors (k′) and Hansch's log P values, showing that hydrophobic adsorption between the gel and the base group is the predominant separation mechanism for both the nucleosides and the bases. In the separation of nucleotides on the GS-320 column, an ion-repulsion interaction appeared to be predominant, as the k′ values were negative and the retention volumes were increased by methylation of the carboxylic groups in the gel but unaffected by additionof acetonitrile to the mobile phase. On the strongly hydrophobic ODS column, nucleoside elution occurred after nucleotide and base elution and more complex correlations were observed, suggesting hydrophobic interaction of the octadecyl group of the gel with the sugar group and also with the base group, particularly for the nucleosides. This interference was supported by an observed increase in the capacity factor of ribose in the presence of antichaotropic sodium chloride on the ODS but not on the GS-320 column. The utility of the GS-320 column for the separation of nucleic acid components was also investigated. Nucleotides, nucleosides and bases were consistently separated, apparently by a hydrophobic adsorption mechanism, permitting the simple, efficient analysis of mixtures of these substances by isocratic elution. © 1990.