Nanozyme catalysis pressure-powered intuitive distance variation for portable quantitative detection of H 2 S with the naked eye.

As a representative gas of food spoilage, the development of rapid hydrogen sulfide (H 2 S) analysis strategies for food safety control is in great demand. Despite traditional methods for H 2 S detection possessing great achievements, they are still incapable of meeting the requirement of portability and quantitative detection at the same time. Herein, a nanozyme catalysis pressure-powered sensing platform that enables visual quantification with the naked eye is proposed. In this methodology, Pt nanozyme inherits the catalase-like activity to facilitate the decomposition of H 2 O 2 to O 2 , which can significantly improve the pressure in the closed container, further pushing the movement of indicator dye. Furthermore, H 2 S was found to effectively inhibit the catalytic activity of Pt nanozyme, indicating that the catalase-like activity of PtNPs may be regulated by varying concentrations of H 2 S. Therefore, by utilizing a self-designed pressure-powered microchannel device, the concentration of H 2 S was successfully converted into a distinct signal variation in distance. The effectiveness of the as-designed sensor in assessing the spoilage of red wine by H 2 S determination has been demonstrated. It exhibits a strong correlation between the change in dye distance and H 2 S concentration within the range of 1-250 μM, with a detection limit of 0.17 μM. This method is advantageous as it enhances the quantitative detection of H 2 S with the naked eye based on the portable pressure-powered sensing platform, as compared to traditional H 2 S biosensors. Such a pressure-powered distance variation platform would greatly broaden the application of H 2 S-based detection in food spoilage management.