Abstract: Purification of synthesized oligonucleotides is achieved using novel processes and reagents. The novel processes involve adding certain salts to treated synthesized oligonucleotides prior to eluting the oligonucleotides from reverse phase purification cartridges. The novel processes also involve treating synthesized oligonucleotides using cleaving and deprotecting reagents containing methylamine and certain salts. Reagents comprising methylamine and certain salts can be used to rapidly cleave and deprotect oligonucleotides while obtaining high yields of purified oligonucleotides using reverse phase purification technologies.