Solving complex anion separation problems with a carbonate–hydrogencarbonate gradient

This paper describes the application of a new suppressor to solve complex anion separation problems with carbonate–hydrogencarbonate gradients. In addition to suppressing the mobile phase and enhancing the analyte signal like any other ion chromatography suppressor, the new DS-Plus suppressor removes carbonic acid from the suppressor effluent when carbonate–hydrogencarbonate mobile phases are used. This greatly reduces the background signal, enabling carbonate–hydrogencarbonate gradients. Since carbonate–hydrogencarbonate mobile phase has stronger eluting power than hydroxide or tetraborate, only dilute concentrations are needed to separate most anions. By adjusting the carbonate–hydrogencarbonate ratio in the mobile phase, various anion mixtures including those containing organic and inorganic anions with −1 to −3 charges can be separated on one or two columns, eliminating the needs for columns with special selectivity.