Determination of iron in sea water by densitometry after enrichment as a bathophenanthroline disulphonate complex on a thin layer of anion-exchange resin

Abstract

A rapid, simple and sensitive method for the determination of trace amounts of iron in sea water has been developed. The method is based on the enrichment of iron as a red bathophenanthroline disulphonate complex by a thin layer of anion-exchange resin followed by densitometric scanning of the thin layer. Except for the chloride, the major constituents and the trace elements of sea water, when present in concentrations found in sea water or higher, did not affect the determination of iron. Chloride ions at concentration levels found in sea water affect the fixation of the iron(II)-bathophenanthroline disulphonate complex on a thin layer of anion-exchange resin. The effect of chloride in sea water samples was reduced by dilution. The concentration of iron in sea water was found to be 2.55 µg l^–1 with a relative standard deviation of 3.5%(n= 11) for 50 ml of sea water.