日本分析化学会 Acta Medica Okayama 0910-6340 4 1 1988 Simultaneous Determination of Sodium and Potassium Ions in River Water by Ion Chromatography Using Silica Gels as a Stationary Phase 81 85 EN Tadashi Iwachido Shoji Motomizu Alkali metal cations were shown to be separable on a silica gel column by cation exchange. Factors affecting the separation of these cations were investigated. Among them, type and concentration of the mobile phase electrolytes profoundly affected the retention of the analyte. The alkali metal cations were well separated on a 150 mm long Zorbax SIL column with 2.1mm i.d., using an aqueous 0.01mol dm(-3) lithium acetate as the mobile phase. Sodium and potassium in river water were determined rapidly with satisfactory accuracy. No potential conflict of interest relevant to this article was reported.