Sensitive immunochromatographic assay for the detection of the dimethachlone fungicide in tomatoes and lettuces

Here, we describe a sensitive and rapid gold nanoparticle-based immunochromatographic strip (GNP-ICS) for the detection of dimethachlone (DMT) in tomatoes and lettuces using GNP-labeled monoclonal antibodies (mAbs) as the probe. Anti-DMT mAbs (1F4) were produced using two haptens and identified by heterologous indirect competitive enzyme-linked immunosorbent assay (icELISA) and had a half maximal inhibitory concentration (IC50) and limit of detection (LOD) of 2.84 +/- 0.07 and 0.67 +/- 0.01 ng mL(-1), respectively. The developed GNP-ICS assay showed high sensitivity and specificity for the detection of DMT with a cut-off and visual limit of detection (vLOD) of 40 and 5.0 ng mL(-1), respectively. Furthermore, the application of these developed immunoassays for the determination of DMT-spiked tomato and lettuce samples was validated by liquid chromatography tandem mass spectrometry (LC-MS/MS) and we found that our developed GNP-ICS assay was suitable for the detection of DMT in real samples.