This buffer is primarily used in immunology and biochemistry research, particularly in complement fixation tests. It helps maintain the stability and functionality of complement proteins, which are essential for immune system responses. The inclusion of Mg2+ and Ca2+ ions is crucial as they act as cofactors for various enzymatic reactions involved in the complement cascade. Additionally, it is employed in gel electrophoresis and other laboratory techniques where a stable pH and ionic environment are required. Its application ensures accurate and reproducible results in studies involving immune system mechanisms and protein interactions.