Sampling and SERS detection of pesticides in air and water using a bifunctional PTFE membrane functionalized with high-index Au trisoctahedrons and ZIF-67.

Monitoring of pesticides in air and water is essential for assessing occupational exposure and ensuring environmental safety. In this study, an integrated point-of-use (POU) surface-enhanced Raman scattering (SERS) platform based on a high-index Au trisoctahedrons (Au TOHs)/zeolitic imidazolate framework-67 (ZIF-67)-decorated polytetrafluoroethylene (PTFE) membrane was developed for the rapid sampling and in situ detection of carbaryl (CBR), diquat (DQ), and paraquat (PQ) in air and water. The high-index facets of Au TOHs generate abundant plasmonic "hot spots", thereby enhancing the sensitivity of SERS, while the porous PTFE film and ZIF-67 provide efficient analyte enrichment. The entire detection process was completed within 5 min. The bifunctional SERS-active substrate exhibited good thermal stability, spatial uniformity, reproducibility, and long-term stability. Strong linear relationships between SERS intensity of characteristic peaks and logarithmic analyte concentrations were obtained for CBR, DQ, and PQ in airborne and aqueous environments, with detection limits of 0.0044-0.94 ppb. In addition, the platform demonstrated good selectivity against interfering pesticides and satisfactory recovery rates. The results were consistent with conventional analytical methods, confirming the reliability of the proposed approach. This work provides a promising strategy for rapid on-site monitoring of pesticide contaminants in environmental media.