A Sensitive and Recyclable capillary-based SERS substrates for in situ detection of trace contaminants in liquid environments

In this study, a capillary coated with silver nanoparticles-modified zinc oxide nanorods (Ag/ZnO NRs) was developed as an ultrasensitive SERS substrate. The aggregation of Ag nanoparticles (Ag NPs) at the tips and sides of ZnO NRs generates high-density three-dimensional “hot spots”, which, together with the photocatalytic activity of Ag/ZnO and the extended light–analyte interaction time afforded by the capillary structure, enables efficient adsorption and in situ detection of trace pollutants. This substrate exhibits excellent SERS performance, achieving a detection limit of 10 -14 M for Rhodamine 6G (R6G), with a relative standard deviation of less than 12%, With in-situ and rapid detection of microplastics in different liquid environments such as seawater and various beverages, the detection limit of polystyrene microspheres is as low as 50 μg/mL. Therefore, our prepared substrate offers a highly sensitive and reusable solution for in-situ, real-time, and rapid monitoring of trace contaminants in liquid environments.