Deep Eutectic Solvents as Novel and Effective Extraction Media for Quantitative Determination of Ochratoxin A in Wheat and Derived Product

An unprecedented, environmentally friendly, and faster method for the determination of
Ochratoxin A (OTA) (a mycotoxin produced by several species of Aspergillus and Penicillium and
largely widespread in nature, in wheat and derived products) has, for the first time, been set up and
validated using choline chloride (ChCl)-based deep eutectic solvents (DESs) (e.g., ChCl/glycerol
(1:2) and ChCl/ urea (1:2) up to 40% (w/w) water) as privileged, green, and biodegradable extraction
solvents. This also reduces worker exposure to toxic chemicals. Results are comparable to those
obtained using conventional, hazardous and volatile organic solvents (VOCs) typical of the standard
and official methods. OTA recovery from spiked durum wheat samples, in particular, was to up to
89% versus 93% using the traditional acetonitrile-water mixture with a repeatability of the results
(RSDr) of 7%. Compatibility of the DES mixture with the antibodies of the immunoaffinity column
was excellent as it was able to retain up to 96% of the OTA. Recovery and repeatability for durum
wheat, bread crumbs, and biscuits proved to be within the specifications required by the current
European Commission (EC) regulation. Good results in terms of accuracy and precision were
achieved with mean recoveries between 70% (durum wheat) and 88% (bread crumbs) and an RSDr
between 2% (biscuits) and 7% (bread).