The current invention provides methods for molecule purification by RP-LC and RP-HPLC that uses unbranched terminal alkyldiols as eluting solvents. In particular, the present invention purifies molecules, particularly proteins and peptides, on reverse phase liquid chromatography columns using a buffer containing either 1,5 pentanediol, 1,6 hexanediol or 1,7 heptanediol.