 This method relies on phase separation by centrifugation of a mixture of the aqueous sample and a solution containing water-saturated phenol and chloroform, resulting in an upper aqueous phase and a lower organic phase (mainly phenol).Guanidinium thiocyanate, a chaotropic agent, is added to the organic phase to aid in the denaturation of proteins (such as those that strongly bind nucleic acids or those that degrade RNA).The nucleic acids (RNA and/or DNA) partition into the aqueous phase, while protein partitions into the organic phase.