The interference of cobalt, nickel and copper in the determination of iron by atomic-absorption spectrophotometry in an air-acetylene flame

Abstract

An investigation of interferences in the determination of iron by atomic-absorption spectrophotometry in an air-acetylene flame is reported. It has been found that three elements, cobalt, nickel and copper, exhibit serious depressive effects, the magnitude of which is strongly dependent on the flame conditions, with respect to both fuel-to-air ratio and the height of the optical path above the burner, and is also dependent on the anion present in the sample solution. The optimisation of the flame for both pure iron solutions and those containing the interfering elements, and means of suppressing these interferences, are discussed. The use of 8-hydroxyquinoline at a concentration equal to or greater than the total concentration of cobalt, nickel and copper is recommended as an effective releasing agent.