Point-of-use SERS approach for efficient detecting chlorfenapyr and emamectin benzoate residues based on Au trisoctahedrons@metal-organic framework modified on polya-mide 6 films.

Health concerns over mixed pesticide residues highlight the need for rapid detection methods. This study developed a multifunctional point-of-use (POU) sensor that integrates separation, enrichment, and surface-enhanced Raman spectroscopy (SERS) using high-index Au trisoctahedrons (TOHs) and metal-organic frameworks (MOFs) on polyamide 6 (PA-6) film. The Au TOHs with sharp tips and high index facets offer excellent SERS performance, while MOFs facilitate analyte enrichment and separation. The flexible PA-6 film was used as an absorbent for the initial adsorption. Using the Au TOHs@ZIF-67/PA-6, we achieved on-site detection of chlorfenapyr (CFP) and emamectin benzoate (EB) in 5 min without pre-treatment, significantly faster than traditional methods. Detection limits were 0.68 ppb for CFP and 0.26 ppb for EB on cucumber surfaces, and 0.95 ppb and 0.13 ppb, respectively, in cucumber juice, well below tolerance levels. This method shows great promise for detecting pesticide mixtures in non-laboratory settings, offering a new POU alternative.