Fast amperometric immunoplatform for ovomucoid traces determination in fresh and baked foods

This paper describes the first immunosensor reported so far for the highly sensitive determination of the egg white allergen, ovomucoid (OM). The approach involves the selective capture of sandwich immunocomplexes formed by capture antibody-target protein allergen-HRP-labeled detector antibody onto carboxylic acid-functionalized magnetic beads (HOOC-MBs). The resulting magnetic bioconjugates were captured on the surface of disposable screen-printed carbon electrodes (SPCE) to perform amperometric detection at −0.20 V vs. the Ag pseudo-reference electrode in the presence of hydroquinone (HQ) and H2O2. The as prepared electrochemical immunoplatform showed a wide range of linearity (0.3–25 ng mL−1), a LOD of 0.1 ng mL−1, which is much lower than those claimed for commercial ELISA kits, and a great selectivity against other white egg allergenic proteins. The developed immunosensor was successfully employed for the simple and accurate determination of trace amounts of OM in unprocessed (eggs and wheat flour) and baked (bread) food samples.