Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Gerdes, M; Spener, F; Meusel, M.
Pseudo homogeneous amperometric immunosensor for the detection of 2,4-D based on a displacement format
QUIM ANAL. 2000; 19: 8-14.
Web of Science
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- Co-Autor*innen der Med Uni Graz
- Spener Friedrich
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- Abstract:
- A pseudo-homogeneous amperometric displacement immunosensor for the detection of the herbicide 2,4-dichlorophenoxyacetic acid is described. The displacement assay is performed on disposable screen-printed carbon electrodes without any washing steps and takes advantage of the cross-reactivity of a monoclonal anti-2,4-D antibody toward immobilised 2-methyl-4-chlorophenoxyacetic acid (MCPA). Due to the low affinity of the antibody toward MCPA (cross-reactivity of approximately 30%), the addition of 2,4-D results in a displacement of previously bound antibody. Subsequently the peroxidase label of the remaining anti-2,4-D antibodies is detected at the carbon electrode by adding hydrogen peroxide and KI as redox mediator, which shuttles the electron transfer between the enzyme and the surface of the electrode at a potential of 0 V vs Ag/AgCl. This pseudohomogeneous assay is compared with a heterogeneous assay format, which includes a washing step after the displacement reaction. To avoid the addition of hydrogen peroxide the co-immobilisation of glucose oxidase was also investigated. With the pseudo-homogeneous assay format a detection limit of approximately 0.1 mug/l 2,4-D was obtained, which complies with the European Union Drinking Water Directives. Data about 2,4-D recovery in spiked water samples are presented.
- Find related publications in this database (Keywords)
- enzyme immunoassay
- enzyme-channeling
- pseudo-homogeneous
- screen-printed electrodes
- 2,4-dichlorophenoxyacetic acid (2,4-D)
- 2-methyl-4-chlorophenoxyacetic acid (MCPA)
- displacement assay
- amperometric immunosensor