Novel time-resolved fluorescent-based multiplex immunochromatography test strip for simultaneous detection of...

The presence of multiple pesticide residues in vegetables has become an increasingly critical concern. Immunochromatography has garnered significant interest for its convenience, sensitivity and speed. However, conventional immunochromatography was typically limited to single-target detection, exhibiting restricted efficiency and high costs in on-site large-scale detection scenarios. Dual-channel time-resolved fluorescent immunochromatography test strip (TRFITS) was developed for the simultaneous rapid detection of imidacloprid (IMI) and tolfenpyrad (TOL) in 15 min. Utilizing the excellent optical properties of time-resolved fluorescent microspheres, this TRFITS enabled better detection sensitivity (0.22 ng/mL for IMI, 11.85 ng/mL for TOL), which was approximately 20 times more sensitive than that of conventional immunochromatography, under optimal conditions. In addition, the TRFITS successfully detected IMI and TOL in vegetables samples with acceptable accuracy. The ability to simultaneously quantify multiple pesticide residues using a single test strip reduces material consumption and lowers operational costs, offering a practical solution for rapid on-site pesticide screening.