DETERMINATION OF IRON BY EXTRACTION DERIVATIVE SPECTROPHOTOMETRY AS FE(II)-BATHOPHENANTHROLINE-PICRATE COMPLEX

A sensitive method for the determination of micro-amounts of iron has been developed based on its reaction at pH = 6,0 with bathophenantroline and picric acid. The complex formed. which is of the type of ion-associated, can be quantitatively extracted into 1,2-dichloroethane and measured by first-derivative absorption spectrophotometry. For Delta-lambda = 5 nm. the calibration graph was a straight line. The limits of detection and quantification were 0.6 and 1.7 ng ml-1. respectively. As the method is practically free from interferences it was successfully applied to the determination of iron in samples as water and foods.