ION EXCLUSION CHROMATOGRAPHY FOR THE TRACE ANALYSIS OF SODIUM, POTASSIUM, MAGNESIUM AND CALCIUM IONS IN WATER CONTAINING INTERFERING CONCENTRATIONS OF AMMONIUM IONS (CATION EXCHANGE, PARTITION CHROMATOGRAPHY)

Ion Exclusion Chromatography has been investigated as a technique for separating trace quantities of sodium, potassium, magnesium and calcium ions in water containing interfering quantities of ammonia. Using water as eluent and a hydroxide-form strong-base anion exchange resin, the interfering ammonia was successfully separated from the metal ions. To effect a separation of calcium and magnesium ions, either individually or together, from sodium and potassium ions, the use of a complexing agent as eluent was required. It was not possible to separate sodium ions from potassium ions. To determine the optimum conditions for separation, various factors were investigated including: choice of resin, inclusion of methanol in the eluent, pH, choice of complexing anion, and concentration of eluent and sample ions.