Abstract
A novel label-free electrochemical impedimetric immunosensor for sensitive detection of ochratoxin A (OTA) was reported. A two-step reaction protocol was elaborated to modify the gold electrode. The electrode was first derivatized by electrochemical reduction of in situ generated 4-carboxyphenyl diazonium salt (4-CPDS) in acidic aqueous solution yielded stable 4-carboxyphenyl (4-CP) monolayer. The ochratoxin A antibody was then immobilized making use of the carbodiimide chemistry. The steps of the immunosensor elaboration and the immunochemical reaction between ochratoxin A and the surface-bound antibody were interrogated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The impedance change, due to the specific immuno-interaction at the immunosensor surface was utilized to detect ochratoxin A. The increase in electron-transfer resistance (ΔRet) values was linearly proportional to the concentration of OTA in the range of 1-20 ng mL-1, with a detection limit of 0.5 ng mL-1. © 2008 Elsevier B.V. All rights reserved.
Original language | English |
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Pages (from-to) | 1888-1892 |
Journal | Biosensors and Bioelectronics |
Volume | 24 |
Issue number | 7 |
DOIs | |
Publication status | Published - 15 Mar 2009 |
Keywords
- Diazonium salt
- Electrochemical impedance spectroscopy
- Immunosensor
- Ochratoxin A