Iron is essential to nearly all known organisms. It is generally stored in the centre of metalloproteins, in the heme complex, and in oxygen carrier proteins. Inorganic iron also contributes to redox reactions in the iron-sulfur clusters of many enzymes, such as nitrogenase and hydrogenase. BioVision's Iron Assay Kit provides a simple convenient means of measuring Ferrous and/or Ferric ion in sample. In the assay, ferric carrier protein will dissociate ferric into solution in the presence of acid buffer. After reduction to the ferrous form (Fe²ᶧ), iron reacts with Ferene S to produce a stable colored complex and give absorbance at 593 nm. A specific chelate chemical is included in the buffer to block copper ion (Cu²ᶧ) interference. The kit measures iron in the linear range of 0.4 to 20 nmol in 50 µl sample, or 8 µM to 400 µM iron concentration in various samples.