Zinquin ethyl ester is a cell-permeable, quinolone-based fluorescent probe used as a zinc indicator. In live cells, cytosolic esterases cleave the ethyl ester group preventing its efflux across the plasma membrane. This probe is UV-excitable and emits in the blue region of the spectrum (excitation 368 nm, emission 490 nm). Zinquin ethyl ester has been used to monitor intracellular zinc fluxes associated with apoptosis.
