An ic-ELISA with carboxymethyl chitosan immunomagnetic beads purification process for the determination of T-2 toxin in cereals

T-2 toxin is a common secondary metabolite of the Fusarium fungi. It is toxic and widely distributed in field crops and during the storage of grains. To detect it, in this study, we developed an indirect competition enzyme-linked immunosorbent assay (ic-ELISA) with Fe 3 O 4 -carboxymethyl chitosan-antibody (Fe 3 O 4 -CMCS-Ab) nanoparticles-based sample purification method. Fe 3 O 4 -CMCS-Ab nanoparticles could eliminate the matrix effect and concentrate T-2 toxin to improve the detection limit and detection capability. The detection limit (LOD) and linear range of the ic-ELISA method with Fe 3 O 4 -CMCS-Ab sample purification were 0.03 ± 0.01 µg/L and 0.07 ± 0.01–1.20 ± 0.02 µg/L, respectively. The assay was validated using wheat, oat, and corn samples. The LODs in wheat, oat, and corn samples were 19.12 ± 0.86, 17.88 ± 0.35, and 20.48 ± 0.57 µg/kg, respectively. • First synthesis of Fe₃O₄–carboxymethyl chitosan–antibody (Fe₃O₄-CMCS-Ab) nanoparticles for efficient sample purification. • Development of a magnetic nanoparticle-assisted ic-ELISA for sensitive and specific T-2 toxin detection. • Integration of sample purification with immunoassay to enhance analytical performance in complex food matrices. • Demonstrated applicability across multiple cereal grains, enabling broad food safety monitoring.