BAPTA, Tetrasodium Salt (1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrasodium salt) is a selective calcium chelator with 105-fold greater affinity for Ca2+ than for Mg2+. This product is a high quality and sensitive compound for calcium signaling studies, investigation of signal transduction and apoptotic cascades, and neuroscience research. When BAPTA forms complexes with Ca2+, a UV spectrum shift from 254 to 279 nm occurs at pH >6.0. BAPTA, Tetrasodium Salt is useful for spectrophotometric monitoring of extracellular Ca2+ levels, with very little sensitivity to pH. Has also been used for the measurement and control of Ca2+ levels in eggs, chromaffin cells, muscle cells, retinal cells, and pancreatic cells. Neuroprotective effects in vitro against excitotoxic damage and spontaneous recurrent seizures, such as epilepsy have also been observed.