Sodium phosphate buffer is widely used in biological and biochemical research due to its ability to maintain a stable pH, typically in the range of 5.8 to 8.0. It is commonly employed in cell lysis, protein extraction, and enzyme activity assays where pH control is critical. This buffer is also essential in chromatography and electrophoresis techniques, including SDS-PAGE, to ensure consistent ion conductivity and protein separation. In immunoassays such as ELISA and Western blotting, it helps maintain optimal conditions for antibody-antigen interactions. Additionally, it is used in diagnostic reagents and pharmaceutical formulations where a physiologically compatible buffering system is required. Its compatibility with many biological molecules makes it a preferred choice in molecular biology and clinical applications.