Reverse-phase columns normally do not perform well in 100% aqueous mobile phase. Dewetting of silica pores or collapse of the alkyl chains of the stationary phase causes a sudden loss of retention in this condition.

Primesep® columns are designed with polar ionizable groups within a stationary phase layer, attracting enough water to keep the column in the wetted state with unfold alkyl chains. Our columns are comparable with YMC-AQ® and Waters Polarity®, but different in selectivity and ability to work in other modes of separation besides a reverse mode, such as normal separation, polar organic separation, ion-exchange, and ion-exclusion. These columns have no end capping chemistry.

Loss-of-end capping is a common cause of changing column properties and lost selectivity. Primesep column has only one type of ligand on silica surface. Loss of this ligand is due to aging or harsh use conditions does not affect relative contribution of each separation mode.