5,5'-Difluoro BAPTA is a difluoro-derivative of BAPTA (HY-100168). 5,5'-Difluoro BAPTA is the most widely used probe for studying cytosolic free Ca2+ by 19F NMR. 5,5'-Difluoro BAPTA has high selectivity for Ca2+. 5,5'-Difluoro BAPTA can inhibit the growth of pollen tube[1][2].