Used in environmental monitoring and water testing laboratories to calibrate instruments and validate analytical methods for measuring sulfide levels in water. Ensures accuracy and reliability in detecting sulfide concentrations, which is critical for assessing water quality in wastewater, surface water, and industrial effluents. Helps maintain compliance with environmental regulations by providing a consistent reference for sulfide analysis. Commonly used in quality control procedures to verify the performance of detection systems such as ion-selective electrodes, spectrophotometers, and titration methods.