Ochratoxin A in Some French Wines: Application of a Direct Competitive ELISA Based on an OTA–HRP Conjugate

Abstract

In the direct-competitive enzyme-linked immunosorbent assay (dc-ELISA) approach, an ochratoxin A–horseradish peroxidase (OTA–HRP) synthesized conjugate was utilized. Fluorescence studies revealed that when excited at 333 nm, the OTA–HRP conjugate shifted in fluorescence from 438 nm to 444 nm. At the 295-nm excitation wavelength, the tryptophan emission peak blue-shifted from 326 nm to 318 nm. Western blot analysis revealed that anti-OTA antibodies specifically binds and recognize the OTA–HRP conjugate. The dc-ELISA showed an IC₅₀ value of 400 ng/L and a linear working range (LWR) value between 100 and 1500 ng/L. The ELISA results were confirmed with high-performance liquid-chromatography (HPLC) analysis to assess the potential of the OTA–HRP conjugate.

Keywords:

• ELISA
• fluorescence
• HPLC
• OTA
• Western blot
• wine

Notes

Note. The first four types of wine were commercially available; the remaining three were obtained from local wine producers.