Fluorescent microsphere-based lateral-flow immunoassay for rapid and sensitive determination of eugenols

In this study, a sensitive monoclonal antibody (mAb) 1B5 against eugenols was prepared based on a novel hapten. Based on this mAb, a paper-based lateral-flow immunoassay (LFIA) was developed using Eu-fluorescent microspheres sensor, that could achieve qualitative and quantitative detection of eugenols within 10 min. Results showed colorimetric values observed by the naked eye were 12.3 µg/kg, 12.3 µg/kg, 37 µg/kg and 111 µg/kg for eugenol, isoeugenol, methyl eugenol, and methyl isoeugenol, respectively, in both water and fish samples. For quantitative detection of eugenol, isoeugenol, methyl eugenol and methyl isoeugenol, the detection ranges were 4.49–48.4 µg/kg, 6.02–66.8 µg/kg, 16.5–150 µg/kg and 47.9–710 µg/kg in water, and 3.9–30.9 µg/kg, 5.9–62.6 µg/kg, 16.7–255 µg/kg, and 44.5–890 µg/kg in fish, respectively. The recovery test and detection in fish demonstrated the reliability of the LFIA in real samples. Therefore, the developed LFIA produced a promising alternative tool for the rapid on-site detection of eugenols.