Abstract: A combination of hydrophilic interaction chromatographic (HILIC) column and a weakly acidic cation-exchange resin (WCX) column was used for simultaneous separation of inorganic anions and cations by ion chromatography (IC). HILIC columns employed SeQuant ZIC-HILIC with a sulfobetaine-zwitterion stationary phase (ZIC-HILIC) and Acclaim HILIC-10 with a diol stationary phase (HILIC-10). When the retention behaviors of analyte ions using two different HILIC columns were investigated in acidic elution condition, analyte anions were strongly retained to HILIC-10, compared to ZIC-HILIC. In contrast, retentions of analyte cations to both HILIC columns were much weaker than those of anions. Thus, a WCX column (TSKgel Super IC-A/C) was connected after a HILIC column in series. The multi-column system could give well-resolved separation of ten ions (Na+, NH4+, K+, Mg2+, Ca2+, H2PO4?, Cl?, Br?, NO3? and I?) with elution of 4 mM tartaric acid plus 8 mM 18-crown-6. This system was applied for simultaneous determination of anions and cations in a vegetable juice sample with satisfied results.

Key words: cation-exchange, HILIC, inorganic ions., ion chromatography