Barium Ion Sensing with Commercial IPG K+ Molecular Probes

Fluorophores containing azacrown ether ionophores can be assembled as particularly powerful, sensitive, and selective turn-on chemosensors, due to their well-known size specificity of the binding domain. Here we quantify the capability of three commercially available chemosensors, marketed for biologically useful K+ sensing as probes for Ba2+ ions. Results are presented from both bulk spectrofluorimetry in aqueous solution, as well as at the single molecule level using single molecule fluorescence microscopy.