Deoxynivalenol (DON) is a mycotoxin produced by certain Fusarium species
and found in a high percentage of wheat and maize grains cultured
worldwide. Although not so toxic as other mycotoxins, it exhibits both
chronic and acute toxicity, and therefore methods for its fast and
accurate on-site determination are highly desirable. In the current
work, we employ an optical immunosensor based on White Light Reflectance
Spectroscopy (WLRS) for the fast and sensitive immunochemical label-free
determination of DON in wheat and maize samples. The assay is completed
in 12 min and has a quantification limit of 2.5 ng/mL in buffer
corresponding to 125 mu g/kg in whole grain which is lower than the
maximum allowable concentrations set by the regulatory authorities for
grains intended for human consumption. Several extraction protocols have
been compared, and the highest recovery (>90%) was achieved employing
distilled water. In addition, identical calibration curves were received
in buffer and wheat/maize extraction matrix providing the ability to
analyze the grain samples using calibrators in buffer. Recoveries of DON
from spiked wheat and maize grain samples ranged from 92.0(+/- 4.0) to
105(+/- 4.0)%. The analytical performance of the WLRS immunosensor,
combined with the short analysis time and instrument portability,
supports its potential for on-site determinations