Used as a standard reference solution in chemical oxygen demand (COD) testing to assess the amount of oxygen required to oxidize organic and inorganic substances in water. This solution provides a known COD value for calibration purposes.

Commonly applied in wastewater treatment plants and environmental laboratories to monitor water quality and evaluate the efficiency of purification processes. It ensures consistent and reliable calibration for spectrophotometers and COD analyzers, enabling accurate measurement of pollution levels in industrial and municipal effluents.