DEAE (diethylaminoethyl) anion exchange is a chromatographic method that uses a negatively charged resin to purify nucleic acids. The resin is typically composed of porous beads with a positively charged amine group on the surface. During purification, the sample containing the nucleic acid mixture is applied to the resin. The negatively charged nucleic acids are then attracted to the positively charged resin, while other impurities, such as proteins and salts, are excluded. The nucleic acids can then be eluted from the resin by changing the ionic strength or pH of the buffer, allowing for further separation and purification.

DEAE anion exchange has been used for nucleic acid purification since the 1960s, and it remains a widely used technique today. Over the years, the method has been refined and optimized, with advances in resin technology and buffer systems allowing for greater specificity and purity.