Electrochemical immunosensors for determination of the pesticides 2,4-dichlorophenoxyacetic and 2,4,5-tricholorophenoxyacetic acids

• Published in: Biosensors & bioelectronics Vol. 11; no. 1; pp. 179 - 185
• Main Authors: Dzantiev, B.B, Zherdev, A.V, Yulaev, M.F, Sitdikov, R.A, Dmitrieva, N.M, Moreva, I.Yu
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1996
• Subjects: 4-dichlorophenoxyacetic acid; 5-T; 5-trichlorophenoxyacetic acid; D; immunoenzyme electrode; pesticides; potentiometric sensor; 2; 4-dichlorophenoxyacetic acid; 4; D; potentiometric sensor; pesticides; immunoenzyme electrode; 5-T; 5-trichlorophenoxyacetic acid
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/0956-5663(96)83725-0

Two immunochemical sensors are described for detection of the pesticides 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). The assay monitors the competitive binding of free pesticide and pesticide-peroxidase conjugate with antibodies immobilized on a graphite electrode, by measurement of peroxidase activity in the immune complexes on the electrode surface. 5-aminosalicyclic acid and H 2O 2 are used as substrates. An automated potentiometric device measures changes in redox potential during the peroxidase reaction. The assay parameters were optimized to achieve detection limits of 40 ng/ml 2,4-D and 50 ng/ml 2,4,5-T (in both water and serum). The total time required to perform the assay (including electrode regeneration) was 12 min, compared to about 2 h for solid-phase enzyme immunoassays. The electrode life extends to 60 sequential measurements. The sensors therefore appear suitable for medical and ecological applications.