Relative Strength of Stronger Solvents for Silica,Amino- and Cyano-alkyl Bonded Silica Columns in Normal-Phase Liquid Chromatography

Abstract

The strength and selectivity of solvents such as ethyl acetate, dioxan and ethyl alcohol in n-hexane binaries were determined using steroids as solutes in normal-phase liquid chromatography of silica gel, amino- and cyano-propyl silica columns. Based on the linear relationship between the logarithm of the capacity ratio and logarithm of solvent composition, the relative strength of solvents was determined from the experimental retention data described in our earlier articles. A micro-computer data base was compiled for filing the retention behavior of the steroids. Using this computer data base, the optimization process of binary solvents for a given sample was improved. An example of the phase system design is described.