HPLC Column Ultisil, Polar-RP, 120 Å, 5 µm, 4.6 x 250 mm

The polar functional group close to the surface increases the wet ability of this phase, thus decreasing phase collapse, making this phase compatible with mobile phase of up to 95% water content. The polar functional group also shields the effects of unreacted silanol groups, providing excellent peak shape for very polar and strong basic compounds and different selectivity than C18 phase. Welch provides two kinds of packing materials - Ultisil Polar-RP and Ultisil Phenyl-Ether.