Discovery of multiple bee-hazardous pesticides in ornamental plants via the Bee-Plex multi-target microsphere screening method

Exposure to pesticides is one of the main drivers of global bee decline. However, the occurrence of pesticides in bee-attracting crops remains underexposed due to the lack of efficient on-site screening approaches for multi-analyte monitoring. Utilizing color-encoded superparamagnetic microspheres, we constructed a portable 8-plex indirect competitive microsphere-based immunoassay for the simultaneous determination of multiple bee-hazardous residues (Bee-Plex). Through a single measurement within 40 min, Bee-Plex exhibited high sensitivities with IC₅₀values of 0.04, 0.08, 0.14, 0.15, 0.78, 0.86, 7.72, and 8.79 ng/mL for imidacloprid, parathion, fipronil, emamectin, carbofuran, chlorpyrifos, fenpropathrin and carbaryl, respectively. Moreover, the implementation of multiple broad-specific antibodies enables a wide-range screening profile for 30 pesticides and pesticide metabolites, detecting 6 neonicotinoids, 6 N-methyl carbamates 6 organophosphates, 5 avermectins, 5 pyrethroids and 2 phenylpyrazoles. The combination of Bee-Plex screening (93% accuracy) and LC-MS/MS confirmatory analysis revealed contaminations of neonicotinoids (100%) and avermectins (70%) in roses, with occurrence frequencies of 79%, 79%, 21%, 21%, 7%, and 7% for imidacloprid, acetamiprid, clothianidin, thiacloprid, imidaclothiz, and nitenpyram, respectively. Above all, this study offers a powerful analytical tool for rapid screening of multiple bee-hazardous pesticides, offering new insights in the occurrence of multi-pesticide contamination in ornamental plants.