A time-resolved fluorescent signal tag-mediated immunochromatographic assay for the rapid and sensitive detection of fluoxetine

The illegal addition of fluoxetine (FLX) to weight-loss products poses significant health risks to consumers. In this study, computer-aided simulation technology was utilized to design and screen FLX hapten. By optimizing the alkyl linker strategy, while preserving the structural similarity with the parent molecule, the hydrophobic interaction was enhanced, thereby significantly improving antibody performance. Based on this strategy, we successfully developed a highly sensitive monoclonal antibody (mAb). Leveraging this, we established an immunochromatographic assay (ICA) utilizing time-resolved fluorescent microspheres (TRFMs) for detecting FLX in capsule, tablet, and beverage samples, with limits of detection (LODs) of 3.010 and 1.549 µg/kg, and 0.886 ng/mL, respectively. Notably, the proposed ICA demonstrated acceptable selectivity, stability, and reproducibility. The recovery rates for FLX in the aforementioned matrices were 97.9 %-101.8 %, 96.9 %-103.4 %, and 99.1 %-101.7 %, respectively. These results were consistent with those obtained via LC-MS/MS. The TRFMs-based ICA provides a reliable, rapid, high-sensitivity, and real-time method for monitoring FLX levels. Moreover, this assay provides a promising strategy for the rapid detection of unauthorized non-food additives in food products.