MOF-based hybrid film for multiphase detection of sulfur dioxide with colorimetric and surface-enhanced Raman scattering readout

Accurate and selective on-site determination of gaseous molecules in real systems has spurred extensive attention because of complicated matrix and low affinities toward analytical interface. Here, we designed a smart film of porous NU-901 wrapping on thiol-magenta modified Ag nanoparticles (TM-Ag@NU-901) as chromogenic and surface-enhanced Raman scattering (SERS) sensor for detection of sulfur dioxide (SO 2 ). Benefiting from the SO 2 -induced nucleophilic addition reaction, the color of TM-Ag@NU-901 can change from deep-red color to pink then to colorless, leading to deterioration of colorimetric intensities and increment of SERS signals. Consequently, TM-Ag@NU-901 film can be used not only as a calibrated scale for visual discrimination towards SO 2 but also as a high-sensitive SERS sensor for credible determination of SO 2 because of their superior extraction performance and affinity toward SO 2 . Importantly, the bimodal strategy offers substantial improvement in accuracy, quantitative performance of SO 2 compared with single-channel method, and facilitates the detection of SO 2 in gas, commercial wine, and food samples in a reliable and rapid feature. The TM-Ag@NU-901 film-based sensing platform is anticipated to pave a venue for in-field applications in various environmental activities and food security.