Immunochromatographic assay for the analysis of methomyl in cabbage and tomato.

• A novel hapten of methomyl was synthesized. • The methomyl concentration generating a 50 % inhibition rate is 49.8 ng/mL. • The cLOD of the ICA strip was 3.2 and 5.4 ng/mL in cabbage and tomato, respectively. • This is the first time that ICA has been applied to detect methomyl. In this study, a hapten of methomyl was designed and used to produce monoclonal antibodies (mAbs) against methomyl. Based on these mAbs, we developed an enzyme-linked immunosorbent assay (ELISA) and immunochromatographic assay (ICA) strip for the determination of methomyl residues. Results from the ELISA showed that mAb 1D10 exhibited higher affinity with an affinity constant of 2.76 × 1010 L/mol and higher sensitivity with a limit of detection (LOD) was 8.12 ng/mL. After optimizing the ICA, a visible limit of detection (vLOD) was found to be 100 ng/g and the cut-off value was 500 ng/g for methomyl in cabbage and tomato. The calculated LODs were 3.2 ng/g and 5.4 ng/g in cabbage and tomato, respectively. Moreover, results from the ICA were consistent with those of the ELISA in our recovery assay using spiked samples. Hence, the ICA method has a bright future and great prospects for the detection of methomyl in food samples. [ABSTRACT FROM AUTHOR]