Retention behaviour of some coumarins in normal-phase high-performance thin-layer and column chromatography

Summary A number of coumarins, furocoumarins and pyranocoumarins were investigated using HPTLC and HPLC systems consisting of silica gel and binary and ternary solvents containing a polar modifier (acetonitrile, dioxane, diisopropyl ether, methyl ethyl ketone, ethyl acetate, 2-propanol or tetrahydrofuran) and a non-polar or weakly polar diluent (n-heptane or dichloromethane). The experimental results obtained on thin layers, under isocratic conditions, showed a linear relationship between the R_M values and the log of the concentration of the polar modifier.The influence of the modifier and the individual substituents in the solute molecule on retention is presented as chromatographic spectra by plotting the R_M and logk values against the mobile phase used.Preliminary communication of this work was presented at the 46th International Congress of Pharmaceutical Sciences, in Helsinki, Finland, 1–5 September, 1986.