Used in biological and biochemical research to maintain a stable mildly acidic pH environment at 5.0. This 0.5M sodium phosphate buffer (PBS) is employed in protocols requiring acidic conditions, such as nucleic acid extraction and precipitation, enzymatic reactions optimized for low pH, and sample preparation for techniques like gel electrophoresis or chromatography. It functions as a diluent or wash buffer in immunoassays, protein purification, and diagnostic procedures where consistent acidic pH is needed to enhance solubility or activity. Also applied in pharmaceutical formulations and research involving acid-tolerant systems. Its buffered and non-toxic nature supports stability in various lab experiments.