A method is provided for separating a dicarboxylic acid product from a mixture containing such dicarboxylic acids. The method involves: providing a dicarboxylic acid-containing mixture of which at least 35% of the carboxylic acid content of the mixture is a dicarboxylic acid product of interest; running an extraction of said dicarboxylic acid-containing mixture through a chromatographic column configured with an amphoteric resin, such that the dicarboxylic acid product elutes preferentially from the dicarboxylic acid-containing mixture. In certain embodiments, the dicarboxylic acid product of interest can be a glucaric or gluconic acid product from a mixture of either or both of these with still other carboxylic acids.