PRECONCENTRATION AND COLORIMETRIC DETERMINATION OF FE(III) BY SEQUENTIAL INJECTION-ANALYSIS

A sequential injection analysis (SIA) assembly for the photometric det ermination of Fe(III) in fresh- and seawater is proposed. Iron is prec oncentrated on a microcolumn packed with a chelating resin (Chelex 100 ) that is inserted in the manifold. The sample is passed through the c olumn, and the iron retained by the resin is subsequently eluted with 2 M HNO3. The Fe-KSCN complex is detected by UV-vis spectrophotometry. The proposed SIA system affords automatic preconcentration, elution, and formation of the iron thiocyanate complex. The detection limit thu s achieved is 0.02 mg/L, and the relative standard deviation 3%. (C) 1 996 John Wiley & Sons, Inc.