Pectin-modified PCN-222 for detecting nitrofurazone residues with dual signals in livestock, poultry, and aquatic products

Nitrofurazone and its metabolite semicarbazide (SEM) residues present in food products pose substantial health hazards to humans. Herein, the colorimetric–fluorescent lateral flow immunoassay (LFIA) for 4[(4-carboxyphenyl)-methylene]-hydrazinecarboxamide (CPSEM) detection was developed using PCN-222@Pectin as a signal tag. Herein, the PCN-222 surface was subsequently modified with pectin to enhance its aqueous solubility and stability. The PCN-222@Pectin-LFIA system exhibited a broad linear range from 0.025 ng/mL to 100 ng/mL. The low limits of detection for the colorimetric and fluorescence-based detection methods were 0.1 and 0.05 ng/mL, respectively. Notably, these values represent a 10- and 20-fold higher sensitivity than that of the traditional colloidal gold nanoparticle-based LFIA. This method was successfully used to detect CPSEM in actual samples, with recovery rates of 89.34 %–120.80 %. This approach fulfills the need for on-site preliminary qualitative assessment during detection and permits subsequent accurate quantitative analysis.