Trace analysis of nitrite ion in seawater using ion chromatography

Abstract

An ion chromatographic method of separating and detecting nitrite in sea water is described. The system includes precolumn, new hydrophilic separation column, suppressor and two-valve system. Nitrite was diverted, trapped and separeted in a 2.6-ml sample loop using 6- and 4-port valves. The eluent used was 14.4 mM sodium hydrogen carbonate at flow-rate oflml/min while the scanvenger was 14 mM sulfuric acid. Nitrite recovery achieved was 100±2%. The minimum detection limit was 0.15 ppm with the signal-to-noise set 2.5 Nitrite recovery obtained using different mixing ratios of sodium hydrogen carbonate and sodium carbonate were lower. Eluent ph and compoosition affected both peak heights and retention timed of nitrite and other anions.