From this graph you can see that there is an exponential increase in retention time for methanol, acetonitrile and THF as the polar solvent increases (organic solvent decreases). This is typical Reverse Phase separation, as is the order of the relative strengths of these solvents. Peak sharpness and symmetry also improve as changes from methanol to acetonitrile and finally to THF are made.

Also shown is the Organic Normal Phase (ONP) analysis of Carvone, where as the percentage of the most polar solvent, isopropanol reduces in concentration, the retention time increases. In this separation as in many others, the peak sharpness and symmetry were best achieved when working ONP.

It should be noted that we normally recommend Ethyl Acetate or THF as a normal phase modifier in preference to Isopropanol for TYPE-C Silica™.