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

• Published in: Analyst (London) 1995, Vol.120 (10), p.2469-2473
• Main Authors: XIAO JUN, LIMA, J. L. F. C, MONTENEGRO, M. C. B. S. M
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/AN9952002469

An ion chromatographic method using a permanently coated C18 reversed-phase column for the rapid (under 2 minutes) determination of sulphate at the pg level using indirect UV detection (205 nm) is described. Potassium hexacyanoferrate(III) and 1,12-diaminododecane were used as eluent and coating reagent, respectively. The coating reagent provided a weak ion-exchange site on the C18 stationary phase. The eluent was chosen for its UV active absorption and its strong elution at low concentrations. The method was applied to 27 different samples including tap water, well water, surface water, waste water and mineral water. The calibration graph was linear from 0.08-10.0 mg sulphate per litre. The results were obtained in good agreement with those obtained by the turbidimetric method. Over a period of 6 days the day-to-day reproducibility as the relative standard deviation for a 1.0 mg sulphate per litre standard was approximately 3.2 per cent for the peak area and approximately 1.7 per cent for the retention time. This method was sufficiently sensitive for the determination of sulphate in the presence of excess amounts of other inorganic ions and organic anions. There are 30 references.