Unveiling the matrix tolerance discrepancies between colloidal gold and quantum dot microspheres-based lateral flow immunoassays for procymidone detection

Colorimetric colloidal gold nanoparticles (AuNPs) and fluorescent quantum dot microspheres (QMs) are widely used signal reporters in lateral flow immunoassays (LFIA), yet their comparative performance in matrix remains insufficiently understood. Herein, AuNPs-LFIA and QMs-LFIA were developed for detecting procymidone residues, with a particular focus on matrix tolerance. Beyond sensitivity differences, these two platforms have exhibited markedly distinct responses in complex vegetable matrices. To better evaluate the overall effects, a matrix interference coefficient (Im) was introduced. By decoupling signal transduction interference from total assay interference, the dominant contribution of immunorecognition disruption to matrix effects was identified. Notably, while both systems were affected by immunorecognition interference and nonspecific adsorption, QMs exhibited higher tolerance in all three selected matrices. QMs-LFIA demonstrated not only an 8-fold enhanced sensitivity, but also maintained reliable performance under substantially lower dilution conditions, which showed good agreement with LC–MS/MS, confirming the accuracy and robustness of the proposed method.