Development of an electrochemical immunosensor for ochratoxin A

A direct, competitive electrochemical enzyme-linked immunosorbent assay (ELISA) has been developed for the quantitative determination of ochratoxin A (OTA) using polyclonal antibodies. The assay is carried out on carbon-based screen printed electrodes (SPE). Optimisation of the ELISA competitive conditions allowed us to realise an assay with improved analytical behaviour compared to the classical spectrophotometric ELISA based assay. The performance was comparable to a published monoclonal based assay. The assay gave a detection limit of 180 pg mL(-1) and sensitivity of 6.1 +/- 0.1 ng mL(-1). The immunosensor was challenged with wine to assess a matrix effect. Recoveries obtained were in the 70-118% range. The method appears to be suitable for OTA contamination screening in food samples.