AbstractRetention behaviour in supercritical fluid chromatography (SFC) with packed columns was investigated using two model mixtures. Xanthine bases (caffeine, theophylline, theobromine) were chosen as a relatively polar group while fat‐soluble vitamins (vitamin A, vitamin D2, vitamin E) were taken as a mixture of lower polarity. — Carbon dioxide based supercritical fluid chromatography of the model analytes was performed on columns with different stationary phases, e.g. alkyl‐, aminopropyl‐ and cyanopropyl‐bonded silica. Retention and selectivity were measured as a function of polar modifier content in carbon dioxide with methanol and 2‐propanol as organic modifiers. The results indicate that retention is not only determined by the molar content of alcohol modifier in the mobile phase but also by its polarity expressed by the Snyder parameter. For the polar solutes the adsorption of modifier molecules on residual silanol groups plays an important role.