Abstract
A rapid spectrophotometric method has been developed for the determination of trace iron by using bathophenanthroline. Bathophenanthroline and ferrous ion form an intensely red colored complex insoluble in water but soluble in ethanolwater mixture. At maximum absorption, 533 mμ, the molecular extinction coefficient of the complex in 10% ethanol is 22, 400. It has been confirmed that the spectrophotometric measurement of the color intensity developed in 10% ethanol offers a rapid and sensitive method for the determination of iron, and the analytical procedure is simpler than in the extraction method.
The color is very stable and the intensity does not change provided the pH range is 26. The absorbancy obeys Beer's law, and 5 ppb of iron can be detected when a 100 mm light path is used. Results of water analysis show a standard deviation of less than 2.3%. Among the diverse ions tested, only copper, cobalt, cyanide and citrate have interfering effects.
