Tetrahydrofuran-Containing Crown Ethers as Ionophores for NH⁺₄-Selective Electrodes

Abstract

), were prepared and the electrode characteristics were tested. The conditioned NH 4 + -ISEs (E1) based on L 1 with TEHP as a plasticising solvent mediator gave best results with near-Nernstian slope of 53.9 mV/decade of activity, detection limit of 10 −4.9 M, and enhanced selectivity coefficients for the NH 4 + ion with respect to an interfering K + ion (log K pot NH 4 + ,K + = -1.84). This result was compared to other ammonium ionophores reported previously, for example, that of nonactin (log K pot NH4 + ,K + = -0.92). The proposed electrode showed no significant potential changes in the range of 3.0 < pH < 9.0.

Inclusion complexes of the macrocycle nonactin with benchmark protonated amines: aniline and serine

“…1 to illustrate the electronegative coordination centres provided by the oxygen atoms from the oxolane (tetrahydrofuran) groups and from the ester linkages of the macrocycle backbone, as well as the hydrophobic rim associated with the methyl side groups and the methylene furan groups. Nonactin and related structures have been taken as core cation-binding motifs in electrochemical sensors 8–18 and in antimicrobial and anticancer agents based on the disruption of ionic channels. 19–23…”