Anion-exchange chromatography
Anion-exchange chromatography is a process that separates substances based on their charges using an ion-exchange resin containing positively charged groups, such as diethyl-aminoethyl groups (DEAE). In solution, the resin is coated with positively charged counter-ions (cations).
Source: Wikipedia — Anion-exchange chromatography (CC BY-SA 4.0)