Flexible superhydrophobic CC/ZIF-8@Au SERS substrate for sensitive and reusable detection of antibiotic residues in complex matrices

Antibiotic residues in food and environmental matrices pose potential risks to human health and ecological safety, creating a need for convenient and sensitive detection platforms. Herein, a flexible superhydrophobic surface-enhanced Raman scattering (SERS) substrate (CC/ZIF-8@Au) is developed for direct detection of antibiotic residues in complex matrices. ZIF-8 is grown in situ on carbon cloth (CC), providing a porous interface for molecular enrichment and a stable platform for the subsequent loading of Au nanoparticles (Au NPs). The integrated ZIF-8@Au architecture synergistically combines analyte enrichment with plasmonic enhancement, while the flexible carbon cloth enables convenient handling and application. Surface modification with n-dodecanethiol endows excellent superhydrophobic properties, suppressing nonspecific adsorption and improving reusability. Systematic characterization verifies structural integrity and chemical stability. The substrate demonstrates good signal uniformity within a single substrate. Furthermore, measurements of ofloxacin (OFL) using independently prepared substrate batches show only minor variations, indicating good batch-to-batch reproducibility. The substrate retains approximately 88% of its initial SERS intensity after four weeks and maintains strong SERS activity after five washing cycles, demonstrating good stability and reusability. In real samples (milk, lake water), OFL and chloramphenicol (CAP) were sensitively detected, with limits of detection (LOD) of 1.253 × 10^-8 M and 7.362 × 10^-7 M, respectively, showing good linearity within the corresponding concentration ranges. Collectively,the flexible superhydrophobic CC/ZIF-8@Au substrate combines molecular enrichment, SERS enhancement, and convenient regeneration, offering a promising approach for SERS detection of antibiotic residues in different matrices.