Used in environmental testing to calibrate instruments for measuring sulfide levels in water and wastewater. Commonly applied in industries such as oil and gas, pulp and paper, and wastewater treatment to monitor sulfur compounds that can cause corrosion, odor, or environmental harm. Also used in laboratory analysis, including ion chromatography and colorimetric methods, to ensure accurate detection and quantification of sulfides. Helps maintain compliance with regulatory standards for water quality and industrial emissions.