Iron sucrose injection is commonly prescribed for iron-deficiency anemia treatment. Ferric iron (iron(III)) and sucrose are the main components of the injection. Due to its medical use, U.S. Pharmacopeia (USP) requires the monitoring of ferrous iron (iron(II)), of which not more than 0.4% should be present. Polarography is the stipulated analysis method. Metrohm Application Note AN-V-127 describes this analysis for commercially available iron sucrose injection ampoules.
Common techniques for the determination of iron, such as atomic absorption spectroscopy (AAS) or inductively coupled plasma (ICP), can only determine the total iron content. While other techniques such as potentiometric titration can distinguish between ferric and ferrous iron, they require multiple analyses or lack sensitivity.
Using polarography it is possible to distinguish between ferric and ferrous iron as both iron species show signals at different potentials, making it the method of choice for the analysis of the limit of iron (Fe(II)) according to USP without any extensive sample preparation. In addition, polarography can be used to confirm the absence of low-molecular weight iron (Fe(II) and Fe(III)) complexes.
Using the 884 Professional VA instrument in combination with viva software ensures maximum precision and reliability.