Application of the log k pair linearity rule and proportionality rule to the RPP mobile phase scales estimation on cyano-silica column

On the basis of literature-reported log k values, the Log k pair linearity rule and the Proportionality rule were found to be also valid in the case of cyano-silica sorbent, whenmethanol, acetonitrile or propane-2-olwere used as modifiers. The RPPscales, reflecting the solvent strength, are in good linear relationship with the experimentally determined log k values. Furthermore, in the case of methanol and acetonitrile, the linear dependence: log k = f(mol%of modifier) was also established. In the function obtained in a such way, the intercept and the slope exhibit an approximate linear dependence. Finally, in the case of methanol, the experimentally obtained log k values are in a satisfactory agreement with the values calculated by the above equation.