Method utilizing magnetic particles to purify deoxyribonucleic acid (DNA) from samples containing trace nucleic acid

The invention provides a method utilizing magnetic nanocomposite to conveniently, quickly and efficiently purify deoxyribonucleic acid (DNA) from medical samples and other samples containing trace nucleic acid. The method comprises the following steps of: (1) taking a sample to be purified, adding the guanidinium lysis solution with the final concentration of 3-6M and the dithiothreitol with the final concentration of 0.01-0.05M, uniformly mixing, and then carrying out full pyrolysis in a water bath for 5-30min; (2) forming a mixture solution containing magnetic particle-DNA composite; (3) separating the magnetic particle-DNA composite from the mixture solution; (4) cleaning; and (5) eluting to obtain the purified DNA. The method can satisfy the requirement of extracting high-quality DNA from the medical samples, and is applied in downstream polymerase chain reaction (PCR) amplification, submarine thermal reactor (STR) somatotyping and other applications; and the method does not need centrifugation, and has q