Nucleic acid material can be effectively separated from a fluid by first contacting the fluid with a positively charged polymer which binds the nucleic acid material. Thereafter, the polymer, having the nucleic acid material bonded thereto, is contacted with a releasing agent which comprises a solution of an alkaline material and a glycol. The solution has a pH of no more than 12 and operates to release the nucleic acid material from the polymer under relatively low temperature conditions, typically no more than 50° C., and in particular instances, no more than 40° C. The glycol material may comprise a monomeric glycol such as ethylene glycol, propylene glycol, or the like, or it may comprise a polymeric glycol such as polyethylene glycol. Also disclosed is a novel positively charged polymer which may be employed in the separation process. This polymer comprises an acidified polyamine, such as polyethyleneimine which has been reacted with a nonacidified polyethyleneimine in a coupling reaction. The acidified polyethyleneimine may be a coarboxylated and/or sulfonated polyethyleneimine.