ION CHROMATOGRAPHY OF INORGANIC IODINE SPECIES USING C-18 REVERSED-PHASE COLUMNS COATED WITH CETYLTRIMETHYLAMMONIUM

Low-capacity anion-exchange columns were developed by sorption of cetyltrimethylammonium on two types of C18 reversed-phase columns which were coated with 1 mM cetyltrimethylammonium in water-methanol mixtures (57:43, v/v, to 45:55, v/v) at 20-degrees-C. The exchange capacities of the columns were estimated by three methods. The high separation efficiency for anions was performed by using a 0.1 M sodium chloride-5 mM sodium phosphate buffer (pH 5.8) as mobile phase. An ion chromatographic system for iodide consisted of the column (polymer-coated silica packing) coated with 1 mM cetyltrimethylammonium in water-methanol (56:44%, v/v), the sodium chloride mobile phase, and ultraviolet or amperometric detection. Good chromatograms for iodide in surface sea waters were obtained without interference by an excess of salts.