US Patent 6914137 Isolation of nucleic acids

A method for extracting nucleic acids from a biological material such as blood comprises contacting the mixture with a material at a pH such that the material is positively charged and will bind negatively charged nucleic acids and then eluting the nucleic acids at a pH when the said materials possess a neutral or negative charge to release the nucleic acids. The nucleic acids can be removed under mildly alkaline conditions to the maintain integrity of the nucleic acids and to allow retrieval of the nucleic acids in reagents that are immediately compatible with either storage or analytical testing.