Colorimetric and SERS dual-signal immunochromatographic assay based on AuDTNB@Ag for the detection of triadimefon

Abstract

Triadimefon (TDF) is a kind of high efficiency, low toxicity, low residue, long duration and strong internal absorption of triazole fungicide, which is widely used in the production of vegetables, tobacco and other agricultural products to prevent and control many diseases. Triadimefon has neurotoxicity, reproductive toxicity and genotoxicity to organisms, and has carcinogenic and teratogenic effects, which is harmful to human health. An immunochromatographic assay based on surface-enhanced Raman Scattering (SERS) was developed in this study. For the stability and sensitivity of SERS probes, a core-shell Au@Ag nanoparticles (NPs) was used to prepare SERS probes, and Raman reporter molecules (DTNB) were embedded into the core-shell structure. The visual limit of detection (vLOD) of the strip was 15.6 ng/mL, which can realize the qualitative detection of triadimefon. The Raman signal exhibits a linear distribution in the range of 7.8–250 ng/mL, and the limit of detection (LOD) was 4.39 ng/mL, which enables the quantitative detection of triadimefon. The strip has no obvious cross-reactivity with tebuconazole (TBZ), hexaconazole (HXZ), myclobutanil (MCN) and difenoconazole (DFZ). The method has good repeatability, and the two concentrations of TDF are repeated 5 times respectively, and the relative standard deviation was between 7.15% and 11.97%. The recoveries in cucumber and tobacco samples were 88.53–117.13%, and RSD was 4.11–7.79%. The immunochromatographic strip based on SERS established in this study can be used for rapid qualitative and quantitative detection of TDF residues. At the same time, this study also provides reference for the detection of other types of pesticides.