SIMULTANEOUS DETERMINATION OF INORGANIC ANIONS AND CATIONS BY ION CHROMATOGRAPHY WITH INDIRECT PHOTOMETRIC DETECTION

Inorganic cations and anions were separated simultaneously on a silica -based Shim-pack WAX-1 column. The method is shown to provide efficien t separation of Ca2+, Mg2+, Cl- and NO3-. Using 1 mM phthalate-6 mM ED TA at pH 6.57 as the eluent, a mixture containing these ions was separ ated in less than 6 min with detection limits of 1.2-2 ng. The effects of the eluent pH, concentration and composition on the retention beha viour of the analytes were studied. Two practical applications are des cribed.