Very sensitive electrochemical magneto immunosensor for the direct determination of ochratoxin A in red wine

P. R. PERROTTA; N. R. VETTORAZZI; F. J. AREVALO; M. A. ZÓN; H. FERNÁNDEZ

Mendoza

Congreso; CONGRESO; ISM 2011 - MYCORED CONFERENCE ON ?STRATEGIES TO REDUCE THE IMPACT OF MYCOTOXINS IN LATINAMERICA IN A GLOBAL CONTEXT; 2011

Ochratoxin A (OTA) is a mycotoxin produced by fungi of the Aspergillus and Penicillium genera. Mainly, OTA is found in improperly stored food and beverages, and may cause different impacts on human and animal health. The International Agency for Research on Cancer (IARC) classified OTA in 2B Group (possibly carcinogenic agent). A level of 2 ìg Kg-1 of OTA in wines has been established by the Regulatory Commission of the European Community (Commission Regulation No. 1881/2006, 2006). In this work, we present an electrochemical magneto immunosensor (EI) for the determination of OTA in red wine samples and their behavior was compared with the official method. This immunosensor was based on protein G functionalized magnetic beads (MBs) as solid phase for affinity reaction between OTA and OTA monoclonal antibody (mAbOTA). A carbon screen printed-electrodes (CSPE) system was used as electrochemical transduction element. This immunosensor was based on a direct competitive assay between OTA in wine samples and OTA labeled with horseradish peroxidase (HRP) (OTA-HRP). The HRP, in the presence of hydrogen peroxide catalyzes the oxidation of pyrocatechol to benzoquinone, whose back electrochemical reduction was detected on a CSPE by square wave voltammetry (SWV). The experimental variables involved in the immunosensor response to OTA were evaluated. The performance obtained for the EI was an analytical range of 0.01 to 20 ppb, detection limit (DL) of 0.008 ppb and IC50 = (0.272 ± 0.081) ppb. In addition, an acceptable accuracy with a coefficient of variation of 5.56 % and very good recoveries (92 to 110 %) were found. This work shows the potential of our EI for the direct measurement of OTA in red wine samples combining SWV as electroanalytical technique with the MBs and CSPE. This EI has great advantages, as direct measurement of red wine samples without a prior pretreatment, small volume of sample, short time consuming of experiments and DL well below those established by the Regulatory Commission of the European Community (2 ìg Kg-1).