I have a polymer sodium polystyrenesulfonate chain which has about 45 monomer unit and each unit contains one -SO3Na group. The chain also has one terminal unit with -COONa group instead of -SO3Na while the other terminal is having a -Br group. To convert these -SO3Na and -COONa group to -SO3H and -COOH groups I have treated them with HCl acid (1 M) and used the pH 1 to do so. Now, as I understand there will be NaCl as side product and I want to remove them. I found both these NaCl and the acid form of the polymer are soluble in water, I tried solvent extraction method using ethyl acetate but failed. Any suggestion will highly appreciated. Thank you in advance.