Chemiluminescent Ion Sensing Platform Based on Ionophores.

We report here an ionophore-based chemiluminescent platform for the selective detection of ions. This method functions on the basis of the ion-exchange between the target ion and the divalent organic cation lucigenin, which luminesces after reacting with hydrogen peroxide in alkaline conditions. Using the K+ ionophore valinomycin, chemiluminescent detection of K+ (from 10 nM to 1 M) was performed on both dichloromethane solutions and polymeric films. While the ionophores ensured excellent selectivity, the detection range could be adjusted with the ratio between the aqueous and the organic phases, and the divalent lucigenin ions also made the sensitivity for divalent target ions higher than conventional ionophore-based ion-selective optodes. The generalizability of the method was shown by changing the K+ ionophore into a Pb2+ ionophore, which successfully realized the highly selective detection of Pb2+ from 0.1 nM to 0.1 mM. Preliminary application of the method was demonstrated with the determination of K+ in diluted human blood serum (five samples), and the results agreed well with those obtained from potentiometric ion-selective electrodes.