The invention relates to a chromatographic device for isolating and/or purifying double-stranded nucleic acids, preferably double-stranded DNA, from a mixture of such nucleic acids with single-stranded nucleic acids, oligonucleotides, mononucleotides, salts and/or other such impurities. The invention also relates to a method for chromatographically isolating and/or purifying same, and to a kit for this purpose.