A material for reverse phase chromatography comprises surface modifying apolar and charged groups bound to a solid support, said charged groups being present in amounts of about 0.25 to about 22% of the surface modifying groups, or in amounts of about 0.01 μmol/m2 to 0.8 μmol/m2 referred to the surface of the solid support for a material with a total amount of surface modifying groups of 3.6 μmol/m2. Such material and suitable purification conditions for active pharmaceutical ingredients (APIs) like peptides can be evaluated by (a) determining the isoelectric point (pI) of the API of interest, (b) choosing a pH in a range where the solid phase material is stable, (c) determining the difference pI−pH and (d) if the difference pI−pH is positive, choosing an anion exchange (AIEX) material, or if the difference pI−pH is negative, choosing an cation exchange (CIEX) material.