The invention provides the use of tetraethylene glycol dimethyl ether for adsorbing nucleic acids to solid phases such as those with silica surfaces. To this end, the invention also provides compositions comprising TDE. Methods are disclosed and claimed to purify nucleic acids from samples, as well as kits useful for performing these methods. Particularly, the invention encompasses methods for the purification of nucleic acids with low molecular weight. The nucleic acids purified by a method of the invention are suited for assays aiming at the detection of a target nucleic acid.