Summary of determined parameters of ACR and ACG in comparison to those of OGB-1.

The subscripts f and s correspond to Ca2+-free and Ca2+-saturated buffer conditions, respectively.*λex = 548 nm.**λex = 525 nm.aData from [21].bData from [16]. 1bData from [16] (λex = 540 nm).cData from [29]. 1c Data from [29] (λex = 525 nm).dData from [48].eAs the absolute fluorescence quantum yield ΦF of ACR and ACG in the Ca2+-free buffer were below the limit of detection, they were estimated relatively. Thus, as reference the absolute fluorescence quantum yields of ACR and ACG in Ca2+-saturated buffer were used [25].