Synthesis and characterization of monoazathiacrown ethers as ionophores for polymeric membrane silver-selective electrodes

Nine monoazathiacrown ethers have been synthesized and explored as ionophores for polymeric membrane Ag+-selective electrodes. Potentiometric responses reveal that the ion-selective electrodes (ISEs) based on 2,2′-thiodiethanethiol derivatives can exhibit excellent selectivities toward Ag+. The plasticized poly(vinyl chloride) membrane electrode using 22-membered N2S5-ligand as ionophore has been characterized and its logarithmic selectivity coefficients for Ag+ over most of the interfering cations have been determined as <−8.0. Under optimal conditions, a lower detection limit of 2.2 × 10−10 M can be obtained for the membrane Ag+-ISE.