Fast determination of sulfate by ion chromatography based on a permanently coated column

Abstract

A method based on a permanently coated C₁₈ column for the fast determination (< 2 min) of sulfate at the picogram level using indirect UV (205 nm) detection is described. Potassium hexacyanoferrate(III) and 1,12-diaminododecane were used as eluent and coating reagent, respectively. Over a period of 6 d the day-to-day reproducibility, expressed as the relative standard deviation for a 1.0 mg l^–1 sulfate standard, is ±3.2% for the peak area and ±1.7% for the retention time. Determinations of synthetic samples incorporating some inorganic ions and some organic anions showed that sufficient resolution in the presence of excess amounts of common ions was achieved. The proposed method was applied to water analysis. The analytical results of 27 different water samples including tap, well, surface, waste and mineral water were in good agreement with those obtained by the turbidimetric method. The paired Student's t-test showed that there was no statistical difference in the results.