In Situ Raman Monitoring of Trace Antibiotics in Different Harsh Water Environments

In situ surface‐enhanced Raman scattering (SERS) is a widely used operando analytical technique, while facing numerous complex factors in applications under aqueous environment, such as low detection sensitivity, poor anti‐interference capability, etc., resulting in unreliable detectability. To address these issues, herein a new hydrophobic SERS strategy has been attempted. By comprehensively designing and researching a SERS‐active structure of superhydrophobic ZnO/Ag nanowires, we demonstrate that hydrophobicity can not only draw analytes from water onto substrate, but also adjust “hottest spot” from the bottom of the nanowires to the top. As a result, the structure can simultaneously concentrate the dispersed molecules in water and the enhanced electric field in structure into a same zone, while perfecting its own anti‐interference ability. The underwater in situ analytical enhancement factor of this platform is as high as 1.67 × 10 11 , and the operando limited of detection for metronidazole (MNZ) reaches to 10 −9 M. Most importantly, we also successfully generalized this structure to various real in situ detection scenarios, including on‐site detection of MNZ in corrosive urine, real‐time warning of wrong dose of MNZ during intravenous therapy, in situ monitoring of MNZ in flowing wastewater with particulate interference, etc., demonstrating the great application potential of this hydrophobic platform. This work realizes a synergistic promotion for in situ SERS performance under aqueous environment, and also provides a novel view for improving other in situ analytical techniques.