Rhod-FF (potassium salt)

Rhod-FF is a difluorinated analog of the cell-impermeant calcium indicator rhod-2. It has a very low affinity for calcium (Kd = 320 ?M) . Low affinity calcium indicators are particularly useful for studying compartments with high concentrations of calcium, such as endoplasmic reticulum, where high affinity dyes will be insensitive to luminal fluctuations. Rhod-FF has excitation/emission maxima of approximately 552 and 580 nm, respectively.