Used in environmental testing and water quality analysis to measure phosphate levels in samples such as wastewater, drinking water, and natural water bodies. Helps calibrate instruments like spectrophotometers and ion chromatographs for accurate detection of phosphate concentrations. Essential in agricultural and soil testing to assess nutrient content and prevent over-fertilization. Also used in industrial processes to monitor boiler water and cooling systems for corrosion and scale control. Supports compliance with regulatory standards by providing reliable reference values in analytical laboratories.