The 1 cc Oasis WCX cartridges contain the Oasis WCX sorbent, which is a polymeric reversed-phase, weak ion exchange mixed-mode sorbent that has been optimized for fast, simple, and highly selective sample preparation of strong basic compounds and quaternary amines. Since the Oasis WCX sorbent is water wettable, it maintains its capability for higher retention and excellent recoveries even if the sorbent runs dry, which means there is no need to take extraordinary steps to keep the sorbent beds from drying out during the critical steps prior to sample loading. These syringe-barrel-type cartridges are designed for use with vacuum manifolds and automated SPE instruments.