https://www.researchgate.net/post/How_can_I_remove_acetic_acid_from_water_when_the_product_contained_is_an_aromatic_amine

depending on the sample, maybe run a column to wash away the acetic acid. Maybe use reverse phase column- load the mixture, wash away the acetic acid, then use methanol or acetonitrile to was off the compound. Essentially, use the column like a large sep-pak cartridge.

For an example, see: http://www.teledyneisco.com/en-us/liquidChromatography/Chromatography%20Documents/Application%20Notes/Removal%20of%20Non-volatile%20Solvents%20with%20RediSep%20Rf%20Gold%20C18Aq%20Columns%20App%20Note.pdf

Try lyophilization