Reprosil columns exist of porous spherical silica gel. Both pore diameter as even particle size can vary. Through the modification of the silica gel, there are many variants of the Reprosil columns. The Reprosil Pur series are ultra pure RP phases that are more stable than other phases because of bidentate endcapping. The Reprosil Pur 120 C18-aq Line is an Äquivalent to Phenomenex Synergi Hydro.