Abstract Total solubility parameters for normal-phase n-heptane-2-propanol compositions were used to empirically predict the retention of unknown hydroxyl aromatic compounds at different mobile phase compositions on μBondapak NH 2, CN and μPorasil columns. A single experimental k′ value was needed to predict k′ values at other mobile phase compositions for an unknown compound. The method of predicting retention was based on two linear relationships derived from the experimental data. A linear relationship was obtained from plots of log k′ vs. log total solubility parameter of the mobile phase for standard hydroxyl aromatic compounds. Next, a linear relationship was obtained by plotting the slope as a function of the intercept from the slope and intercept values derived from the log k′ plots. Combined, the two linear relationships permitted the prediction of retention at different mobile phase compositions for compounds structurally similar to the original data set.