Real-time quantitative detection of H2S for assessing fish freshness using a gas-controlled micro-drainage device

Hydrogen sulfide (H2S), a potential indicator of fish freshness, necessitates the development of rapid quantitative detection methods for ensuring food safety. Nevertheless, most of the current methods for H2S detection cannot simultaneously meet the requirements of ease-of-use and quantifiability. In this study, we introduce an innovative quantitative detection method of H2S that employs a gas-controlled micro-drainage device with an electronic balance as readout. When H2S, a product of fish spoilage, is present, it interacts with Platinum nanoparticles (PtNPs)-catalase nanozyme, affecting their catalytic activity and, subsequently, the weight of overflowed water. This allows for the conversion of H2S concentration into a measurable weight change signal. The sensor demonstrates an inverse correlation between the mass of overflowed water and H2S concentration (0–50 μM) with a detection limit of 0.43 μM. This device enables sensitive, real-time, and quantitative weighing analysis of H2S to assess fish freshness during storage, offering an effective solution to traditional limitations.