BAPTA (1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid) is an aminopolycarboxylic acid with a high affinity for calcium. It is a white solid. It is used in research to chelate Ca2+, as it behaves similarly to EGTA and EDTA.
Complexation
BAPTA, as its conjugate base, binds calcium ions as a decadentate ligand: