Abstract: This invention relates to a simple and rapid method for the extraction and purification of small RNA from a sample solution. Accordingly, a sample is first mixed with an organic solvent to form a mixture containing the solvent. The mixture is applied to a first mineral support for large RNA to bind. The filtrate is collected which contain unbound small RNA, and is mixed with a second organic solvent to form a second mixture containing the second solvent. This second mixture is applied to a second mineral support for small RNA to bind. After a wash step, the small RNA is eluted. Also provided is a method for the isolation of large RNA, by eluting the large RNA from the first mineral support. In addition, total protein is present in the filtrate and can be isolated by a conventional method.

Abstract: The invention provides an modified method for the separation of nucleic acids from cells, comprising: generating an aqueous solution containing the nucleic acid by lysing the cells with a lysis solution including SDS and salt; and separating the nucleic acids of interest from other cellular components. The improvement includes adding a non-ionic detergent in the lysis solution such that SDS is not precipitated and no heating of the solution is required prior to cellular lysis. The preferred non-ionic detergents are the polysorbate family of compound, including TWEEN® 20. Also disclosed are composition and kit for performing the modified method.