BAPTA tetrasodium is a selective chelator for calcium. BAPTA tetrasodium, as calcium indicator, has high selectivity against magnesium and calcium. BAPTA tetrasodium is widely used as an intracellular buffer for investigating the effects of Ca2+ release from intracellular stores or influx via Ca2+-permeable channels in the plasma membrane. BAPTA tetrasodium can also inhibit phospholipase C activity independently of their role as Ca2+ chelators[1][2][3].