FIGURE 4.

Effect of other species on emission from sensor 5: (A) Emission from 5 (10 µM) is invariant (both alone and in the presence of 5 mM Ca²⁺) above pH 6.5 but increases at more acidic values. (B) Emission enhancement from 5 in the presence of 1 mM various cations. (Cations were added as perchlorate salts as solutions in acetonitrile (MeCN) with the exception of Me₄NClO₄ which was added as a solution in dimethyl sulfoxide (DMSO). All experiments were conducted in 20% (4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid) (HEPES) (10 mM, pH 7.4)/MeCN, [5] = 10 µM, λ_ex = 355 nm.