Flow injection with an integrated retention/photometric detection unit for the determination of iron in water

Abstract

An integrated retention/photometric detection method for the determination of microamounts of iron was developed. The method is based on the retention of the reaction product of the analyte with ferrozine in a flow cell packed with an anion exchange support, and on the subsequent elution of the retained complex with a solution of 1.5% sodium peroxide, which allows the reuse of the system. The method is highly selective and has a detection limit (3 sigma) of 4.3 ng ml(-1). Iron was thus determined in the range 10-200 ng ml(-1) with a relative standard deviation of 1-3% (n = 11). The method was applied to the determination of iron in tap and river water and the results were consistent (2%) with those provided by AAS.