Used in environmental monitoring and water quality testing to detect and quantify common anions such as fluoride, chloride, bromide, nitrate, sulfate, phosphate, and nitrite in drinking water, wastewater, and natural water sources. These mixtures serve as calibration standards in ion chromatography, ensuring accurate measurement of ionic contaminants. They are essential in assessing pollution levels, monitoring nutrient runoff in agricultural areas, and controlling disinfection byproducts in water treatment plants. Also used in industrial process control, soil analysis, and research laboratories studying nitrogen and sulfur cycles.