Ion chromatography apparatus including (a) a chromatographic column, (b) a source of an aqueous eluent liquid stream, (c) a detector, (d) a recycle line between the detector and the chromatographic column, and (e) a purifying device disposed along the recycle line including ion exchange removal medium. Also, such apparatus with an electrolytic purifying device disposed along the recycle line. Also, methods of using such apparatus.