A portable gas pressure meter-based analytical kit for rapid analysis of S^2- in water samples and food additives

Sulfide ions (S^2-) are a hazardous pollutant present in our daily lives; thus, the accurate detection of S^2- is critical for human health. However, conventional analytical methods have the disadvantage of high costs, complex operations, and the need for laboratory analysis. In this work, a miniaturized analytical kit was established for rapid analysis of S^2- in water samples and food additives. In the presence of platinum nanoparticles (NPs), H₂O₂ was decomposed to O₂ catalyzed by Pt NPs, resulting in a substantial increase in pressure inside the sealed reaction bottle. In the presence of S^2-, S^2- forms a Pt-S bond with Pt NPs and induces aggregation, thereby reducing the catalytic activity of Pt NPs, resulting in a decrease in O₂ production and a corresponding decrease in gas pressure. Thus, the analysis of S^2- was achieved by the measurement of gas pressure. S^2- concentrations were inversely proportional to the gas pressures within a linear range of 0.2-5 μg/mL. A portable analytical kit was fabricated for rapid analysis of S^2- in various samples, achieving recoveries of 90-109%, confirming its suitability as a potential analytical device for on-site environmental analysis and rapid food inspection.