Role of mobile phase components for multi-functional solutes in silica gel liquid-solid chromatography. Resolution of...

To improve the resolution of a given sample mixture in liquid-solid chromatography, the characteristics of various components in the mobile phase were determined with a mixture of closely related compounds associated with DNA oligomer synthesis. Water (S0) was added so as to reduce peak tailing efficiently, but in amounts that would not significantly diminish retentivity in the silica gel column. The role of the stronger solvents, such as 1-propanol (S1) and dioxane (S2), in n-hexane (W) as diluent was quantitatively evaluated to control the retentivity. A linear correlation was found between the logarithms of the capacity ratios and molar concentration of the stronger component in the ternary solvent mobile phase. The selectivity of two stronger solvents was incorporated into the phase system to increase the resolution function for four given samples. A quaternary solvent system (W + S1 + S2 + S0) was prepared by integrating the characteristics of all the components, as determined by regression analysis. The multi-component phase system led to a high degree of resolution. This effective procedure was found suitable for analytical and preparative purposes in the resolution of various complex mixtures.