Rhod-2 (potassium salt) is a water-soluble, red fluorescent calcium indicator. It exhibits a significant shift in fluorescence intensity upon calcium binding (ex max = 549 nm; calcium-free
v. ex/em max = 552/581 nm; calcium-bound).
1,2 Unlike the UV-excitable indicators fura-2 and indo-1 , there is no accompanying spectral shift.
