Tetrasodium 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetate, commonly known as BAPTA tetrasodium salt, is a selective chelating agent primarily used in biological and biochemical research for buffering and controlling intracellular calcium ion (Ca²⁺) concentrations. Its high affinity and selectivity for calcium over other divalent cations make it invaluable in studies of calcium signaling pathways, cellular physiology, and neuroscience. BAPTA is employed in cell culture experiments, fluorescence microscopy with calcium indicators, and electrophysiological recordings to mimic or block calcium-dependent processes. It is also utilized in some analytical applications for calcium quantification and in pharmaceutical research for drug screening involving calcium channels. Unlike general chelators, its specificity minimizes interference from other metal ions, enhancing experimental precision.