Patent ID: 7416845

Claim:
A pH dependent ion exchange material having a carboxyl group, an amino group, and a polyethylene oxide moiety, which is used for isolating a nucleic acid, the pH dependent ion exchange material having at least two monomers selected from the group consisting of M0, M1, M2, M3 and M4 represented by the following formulae, provided that the pH dependent ion exchange material has at least one monomer selected from the group consisting of M1 and M2 and at least one monomer selected from the group consisting of M3 and M4: wherein A is a base selected from the group consisting of —NH(CH 2 ) n NH 2 and —NH(CH 2 ) n Y, wherein n is an integer from 1 to 10 and Y is an aromatic base in which at least one of ring atoms is nitrogen, B is —(CH 2 CHO) n OR 2 , wherein n is 1-20 and R 2 is a C1-10 alkyl group or a protecting group, R 3 is —(CH 2 ) 3 and the pH dependent ion exchange material having a degree of polymerization of 2-30,000.