UV-light-driven synthesis of Ag-Zn nanoparticles encased in hydrogels for H2S sensing

Despite the existence of reliable and accurate analysis methods for determining volatile sulfides in food matrices, special efforts have been devoted to the development of online and real-time nanosensors for discriminating volatile sulfides in food products to achieve non-destructive testing of food spoilage. In this research, the UV-light-driven synthesis of Ag-Zn nanoparticles (NPs) hydrogel is reported for low detection limit and high sensitivity colorimetric detection of volatile sulfides. A detection mechanism was designed using the chemical transformation of Ag-Zn NPs to Ag2S-Zn NPs and Zn NPs upon reacting with volatile sulfides, which triggers the supersaturation-induced etching-stripping mechanism, leading to a color change of the Ag-Zn NPs hydrogel from yellow to brown and finally to pale brownish-grey depending on the concentration of volatile sulfides. This enables a naked-eye readout and UV–vis quantitation of the volatile sulfide exposure. A limit of detection of 2 mg/m3 for hydrogen sulfide (H2S) was obtained, which can be used to monitor the spoilage of chilled broiler meat products.