Modification of the ferrozine technique to analyze iron contents in different foods: comparative study using an internal standard as reference methodology.

A methodology for the determination of iron in foods fortified with this element or in nutritional products is important and has to be sensitive and rapid. In developing countries, an inexpensive and reliable methodology is also required. For this purpose, the Gordon's Ferrozine technique was slightly modified and assayed with yogurt, dry powdered milk, and cereal mixtures, all of them fortified with iron, using an internal standard as the reference methodology. The obtained results demonstrate a close correlation between the standard curve interpolation method and the internal standard reference method (correlation coefficient r2 = 0.9950) in a wide range of concentrations. The slope (0.9998+/-0.0040) demonstrates that both procedures measure equal amounts of iron. The conclusion is that the proposed technique is a reliable, practical, and inexpensive methodology for iron determination in different foods fortified with iron.