Inner filter effect-based immunoassay for the detection of acetamiprid using upconversion nanoparticles and gold nanoparticles

In this study, we present an inner filter effect-based immunoassay (IFE-IA) for the detection of acetamiprid with a turn off–on model. In the IFE-IA, the monoclonal antibody (mAb) conjugated with upconversion nanoparticles (UCNPs) were set as a fluorescence source, and the antigen conjugated with gold nanoparticles (AuNPs) were set as the fluorescence switch off reagent, while acetamiprid acts as the fluorescence turn-on reagent. After optimization, the concentration of acetamiprid producing 50% saturation of the signal (SC50) was 0.04 µg/L, and the detection range (SC10–SC90) was 0.002–0.58 µg/L. The IFE-IA showed no cross-reactivity with the analogues of acetamiprid except for thiacloprid (36.4%). The average recoveries of the immunoassay for spiked samples were in the range of 75.1–104.7%. In addition, the assay showed good correlation with high-performance liquid chromatography in the detection of blind samples.