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 ([email protected]) as chromogenic and surface-enhanced Raman scattering (SERS) sensor for detection of sulfur dioxide (SO2). Benefiting from the SO2-induced nucleophilic addition reaction, the color of [email protected] can change from deep-red color to pink then to colorless, leading to deterioration of colorimetric intensities and increment of SERS signals. Consequently, [email protected] film can be used not only as a calibrated scale for visual discrimination towards SO2 but also as a high-sensitive SERS sensor for credible determination of SO2 because of their superior extraction performance and affinity toward SO2. Importantly, the bimodal strategy offers substantial improvement in accuracy, quantitative performance of SO2 compared with single-channel method, and facilitates the detection of SO2 in gas, commercial wine, and food samples in a reliable and rapid feature. The [email protected] film-based sensing platform is anticipated to pave a venue for in-field applications in various environmental activities and food security.