1993 Volume 42 Issue 6 Pages 343-349
A suppressor switching method was studied for the simultaneous determination of organic acids and cations in beverages by ion chromatography with 1.5 mM oxalic acid (flow rate 0.8 ml/min) as an eluent which can be used for the separation of anions and cations. An anion exchange column (Yokogawa SAM3-075, 4.9 mm i.d.×75 mm) and a cation exchange column (Yokogawa ICS-C25, 4.6 mm i.d.×125 mm) were connected in series. An anion suppressor and a cation suppressor were connected in parallel so that the selection of flow could be made for cations and anions. When the effluent from the columns flows through a cation suppressor of a cation exchange membrane type, the cations were suppressed and only anions were detected. If the flow of effluent from columns is changed to anion suppressor by valves, only cations were detected. The main anions (organic acids and inorganic anions) in beverages were separated at 40°C within 40 min when 10 mM sulfuric acid at a flow rate of 1.0 ml/min was used as a regenerant for cations. The cations (Na+, NH4+, K+, Mg2+, Ca2+) were eluted at 40°C within 35 min when 50 mM NaOH was used as a regenerant for anions. This method was applied to the determination of both anions and cations in wine and Japanese sakes with a good reproducibility.
