Synthesis of a capillary surface-enhanced Raman scattering substrate integrating sampling and detection based on meniscus self-assembled technology.

A method is proposed to fabricate a novel capillary surface-enhanced Raman scattering (SERS) substrate integrating sampling and detection based on meniscus evaporation self-assembled technology, named Meniscus@AgNPs@Capillary substrate. Ag nanoparticles (AgNPs) were arranged in the inner wall of the capillary through meniscus evaporation. The parameters which might affect the deposition of AgNPs during evaporation were investigated, including the evaporation temperature, self-assembly time, the ratio of silver sol to ethanol, and capillary length. The enhancement effect of SERS under different fabrication conditions was investigated using rhodamine 6G (R6G) as a Raman probe. Moreover, the optimal fabricated Meniscus@AgNPs@Capillary substrate was applied to the detection of several environmental pollutants such as polystyrene nanoplastics (PSNPs) and various antibiotics, with limits of detection (LOD) of 10 µg/L and 1 µg/L, respectively. The Meniscus@AgNPs@Capillary substrate presented the advantages of time and effort saving, high sensitivity, and on-site sampling and testing.