A ratiometric probe for the selective time-gated luminescence detection of potassium in water

A europium probe for the ratiometric detection of potassium in water is presented. This probe demonstrates high sensitivity, with an affinity for K+ in the mM range, and high selectivity for K+ over Na+, Ca2+, Mg2+ and Li+. The long luminescence lifetime of the probe and its large Stokes shift further enable accurate determination of the concentration of K+ in complex aqueous media.