Used in water quality analysis to detect and quantify common anions such as fluoride, nitrate, nitrite, sulfate, and phosphate in environmental and drinking water samples. These mixtures serve as calibration standards in ion chromatography, ensuring accurate measurement of anion levels for regulatory compliance and pollution monitoring. Also applied in agricultural testing to assess soil and fertilizer composition, helping optimize nutrient management. In industrial processes, they support quality control in wastewater treatment by monitoring anion removal efficiency. Their use extends to food and beverage testing, where nitrate and nitrite levels are regulated for health reasons.