We developed a method for selective purification of DNA using the cationic detergent, cetyltrimethylammonium bromide (CTAB), accompanied with urea and controlled high-salt (NaCl) concentration. This method is effective for rapid separation of DNA fragments from artifacts such as PCR primer dimers or ligation adapters. The CTAB-associated purification completely removed the short PCR artifacts and primers, as well as enzymes and buffer, while recovering a sufficient quantity of amplicons for subsequent experiments such as preparation of libraries. This method could also be applied to the fractionation of nucleic acids generated by other types of reactions.
