The present invention provides a method for isolating biopolymers, particularly nucleic acids, such as DNA or RNA or hybrid molecules of DNA and RNA, from an aqueous solution utilizing magnetic particles, particularly silica magnetic particles. The method of the present invention involves forming a complex of the magnetic particles and the biopolymer in a mixture of said particles and said aqueous solution, comprising a salt and an additive; separating the complex from the mixture by a magnetic force, and eluting the biopolymer from the complex, wherein advantageously no substantial clustering of said magnetic particles occurs during the performance of the method. In a preferred embodiment the method of the invention is performed as an automated process.