title: Cesium-ion selective electrodes based on calix[4]arene dibenzocrown ethers.
abstract: Four calix[4]arene dibenzocrown ether compounds have been prepared and evaluated as Cs(+)-selective ligands in solvent polymeric membrane electrodes. The ionophores include 25,27-bis(1-propyloxy)calix[4]arene dibenzocrown-6 1, 25,27-bis(1-alkyloxy)calix[4]arene dibenzocrown-7s 2 and 3, and 25,27-bis(1-propyloxy)calix[4]arene dibenzocrown-8 4. For an ion-selective electrode (ISE) based on 1, the linear response concentration range is 1x10(-1) to 1x10(-6) M of Cs(+). Potentiometric selectivities of ISEs based on 1-4 for Cs(+) over other alkali metal cations, alkaline earth metal cations, and NH(4)(+) have been assessed. For 1-ISE, a remarkably high Cs(+)/Na(+) selectivity was observed, the selectivity coefficient (K(Cs,Na)(Pot)) being ca. 10(-5). As the size of crown ether ring is enlarged from crown-6 (1) to crown-7 (2 and 3) to crown-8 (4), the Cs(+) selectivity over other alkali metal cations, such as Na(+) and K(+), is reduced successively. Effects of membrane composition and pH in the aqueous solution upon the electrode properties are also discussed.
authors.affiliation: Department of Chemistry, Konyang University, Nonsan, 320-800, South Korea.
authors.forename: J
authors.initials: J
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Ohki
authors.forename: R
authors.initials: R
authors.lastname: Ueki
authors.forename: T
authors.initials: T
authors.lastname: Ishizuka
authors.forename: T
authors.initials: T
authors.lastname: Shimotashiro
authors.forename: S
authors.initials: S
authors.lastname: Maeda