Detection of ferritin in human serum with a MAP–H2O2–HRP voltammetric enzyme-linked immunoassay system

A voltammetric enzyme-linked immunoassay based on new system of m-aminophenol (MAP)–H2O2–horseradish peroxidase (HRP) has firstly been developed and used for the detection of HRP, labelled HRP and ferritin in human serum. HRP or labelled HRP catalyzes the oxidation reaction of MAP with H2O2, the product of which produces a sensitive voltammetric peak at potential of −0.46 V (vs. SCE) in Britton–Robinson (BR) buffer solution. By using this voltammetric peak, HRP can be measured with a detection limit of 9.5×10−1 mU/l and a linear range of 2.5–2.5×102 mU/l. The detection limit to ferritin is 0.25 ng/ml and the linear range 0.25–320 ng/ml. The processes of the electro-reduction of the product of the enzyme-catalyzed reaction have been investigated in detail.