Salicylate selective electrode based on a biomimetic guanidinium ionophore

A biomimetic strategy was employed in the development of oxoanion-selective ionophores containing the guanidinium functional group. These ionophores mimic the selective interaction observed between arginine residues of proteins and oxoanions. In previous work, it was demonstrated that a structurally rigid guanidinium ionophore exhibited excellent hydrogen sulfite selectivity (Anal, Chem. 1994, 66, 3188-3192). Herein, we describe guanidinium-containing ionophores that are selective for the oxoanion salicylate. The ability to rationally design anion-selective electrodes through this biomimetic strategy, and to both alter selectivity and improve response characteristics through structural changes to the ionophore, has been demonstrated. H-1-NMR complexation and modeling studies were used to examine and correlate the selectivity observed with the structure of the guanidinium compounds.