Chromatographic loading solutions for use in the purification of trityl-on oligonucleotides. The solutions comprise an antichaotropic ion, a chaotropic ion, an alkaline salt, and a polar protic solvent, all at particular concentrations. The solution is useful in purifying oligodeoxyribonucleotides and oligoribonucleotides having either ACE or TBDMS protective caps. Also, methods and systems for purifying trityl-on oligonucleotides comprising the chromatographic loading solution, a reversed-phase sorbent, and the oligonucleotides to be purified.