Prediction of oligodeoxyribonucleotides eluting salt conditions on anion exchange column

Chromatography is commonly used as a purification method for synthetic oligodeoxyribonucleotides (1). Anion exchange chromatography on Mono Q column (Pharmacia), under denaturing conditions and using non-organic buffers, gives adequate purity for sequences up to 50 bases long (2). The eluting NaCl concentration primarily depends on the oligonucleotide length. However, base composition and sequence also influence these eluting concentrations (Figure 1). We elaborated a simple experimental law which predicts eluting NaCl concentrations for oligonucleotides, on the basis of their base composition and length.