Determination of Sulfate Ion in Sodium Chloride Reagents by Means of Ion Chromatography after Preconcentration Using Zirconium-Loaded Cation Exchange Resin

Abstract

The conditions for concentrating trace sulfate ion in sodium chloride reagent using a zirconium-loaded cation exchange resin cartridge were examined. Sulfate ion contents were determined by means of ion chromatography after sulfate ion preconcentration.
The suitable pH range for sulfate ion adsorption was found to be from 2 to 4. Absorbed sulfate ions were eluted using 5ml of 0.05M sodium hydroxide. Sulfate ions were also adsorbed in 20% sodium chloride solution. The minimum limit of determination was 0.02mg/kg when 50ml of a 10% sample solution was concentrated. The trace sulfate ion contents of sodium chloride reagents of volumetric-analysis, special, extra-pure and pharmacopoeia grades were determined with this method.