Detection of TMV with ODA-H 2O 2-HRP voltammetric enzyme-linked immunoassay system

Abstract

o-Dianisidine (ODA)-H 2O 2-horseradish peroxidase (HRP) voltammetric enzyme-linked immunoassay system has firstly been used for the detection of tobacco mosaic virus (TMV). HRP catalyzes strongly the oxidation reaction of ODA by H 2O 2, the product of which produces a sensitive second order derivative linear sweep voltammetric peak at potential of −0.56 V (versus SCE) in Britton–Robinson (BR) buffer. HRP activity has been measured with this voltammetric peak and TMV detected through immunoreaction. The detection limit for HRP is 9.25×10 -7 mU l −1 and the linear range is 2.5×10 −6–5.0×10 −4 mU l −1. The detection limit for the clarified TMV is 0.25 ng ml −1 and the highest dilution ratio detected for the infected leaf sap is 1:8×10 5. The sensitivity for TMV detection with this method is higher than that with the enzyme-linked immunosorbent spectrophotometric assay (ELISA) using ODA-H 2O 2-HRP system. The processes of the enzyme-catalyzed reaction and the electro-reduction of the product of the enzyme-catalyzed reaction have been described.