Practice question

DEAE, diethylaminoethyl cellulose, is a weak anion exchanger carrying positively charged groups that attract negatively charged analytes. Binding strength correlates with net negative charge density at given pH. Molecules with higher negative charge interact more strongly, requiring higher salt concentration for displacement. Therefore, among proteins, the most acidic, most negatively charged species retains longest and elutes last during ionic strength gradient, whereas positively charged or neutral proteins pass through or elute early. This principle enables separation of isoforms, nucleic acids, and proteins based on pI differences, optimizing pH to modulate selectivity.