Which are the three steps in iron determination from transferrin?

Which are the three steps in iron determination from transferrin?

• A. Acidification, Reduction, Color development
• B. Dialysis, Precipitation, Titration
• C. Chelation, Oxidation, Spectroscopy
• D. Filtration, Centrifugation, Measurement

Answer: (A)

Determining iron from transferrin relies on a sequence that liberates the metal from the protein, makes it capable of forming a colored complex, and then measures that color. Acidification destabilizes the transferrin-iron complex, releasing iron from the protein, typically as Fe3+. The next step is reduction, converting Fe3+ to Fe2+, because the common colorimetric reagents (such as ferrozine or 1,10-phenanthroline) form a stable, intensely colored complex specifically with Fe2+. Finally, the color development step creates a chromophore whose intensity is proportional to the iron concentration and is measured spectrophotometrically. This combination—releasing iron, reducing it to the proper oxidation state, and forming a measurable colored complex—is what makes the acidification, reduction, and color development sequence the correct approach. The other sequences either omit the essential release, rely on non-colorimetric steps, or do not produce a chromophore that directly reflects iron content.

Determining iron from transferrin relies on a sequence that liberates the metal from the protein, makes it capable of forming a colored complex, and then measures that color. Acidification destabilizes the transferrin-iron complex, releasing iron from the protein, typically as Fe3+. The next step is reduction, converting Fe3+ to Fe2+, because the common colorimetric reagents (such as ferrozine or 1,10-phenanthroline) form a stable, intensely colored complex specifically with Fe2+. Finally, the color development step creates a chromophore whose intensity is proportional to the iron concentration and is measured spectrophotometrically. This combination—releasing iron, reducing it to the proper oxidation state, and forming a measurable colored complex—is what makes the acidification, reduction, and color development sequence the correct approach. The other sequences either omit the essential release, rely on non-colorimetric steps, or do not produce a chromophore that directly reflects iron content.