Biological assays copper complexation

Ferrozine 3-(2-pyridyl)-5,6-bis(4-phenylsulphonic acid)-1,2,4-triaz-ine (Fig. 4.3) reacts with iron in the iron(II) ferrous state to form an intense pink complex which can be measured spectrophotometrically (lmax = 562 nm). The assay can be performed at pH 1.6 to eliminate interference from turbidity at pH values close to the isoelectric points of proteins which may be present in biological samples under investigation, e.g., serum, and in some instances to decrease interference in the assay from copper (see below). In determinations in which such problems are not considerations, the assay may be carried out at pH 7.4. (This might be more relevant for the assessment of membrane-bound iron under in vivo conditions.)... 

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