Use of a flow-injection system in the evaluation of the characteristic behavior of neutral carriers in lithium ion-selective electrodes

Abstract

A flow-injection system based on microconduits is used to investigate electrode characteristics such as selectivity, detection limit, and response and equilibrium times of the new ionophore, N,N,N’,N’-tetraisobutyl-5,5-dimethyl-3,7-dioxanonane diamide, in lithium ion-selective electrodes. These characteristics were compared with those of the ionophore N,N’-diheptyl-N, N’,5,5-tetramethyl-3,7-dioxanone diamide. The new ionophore has superior detection limits and shorter response and equilibrium time, but the other exhibits better selectivity for lithium with respect to sodium. Values of Kz’, for the new ionophore vary from 0.0450 to 0.566, depending on the methods of measurement and solution conditions. This phenomenon is discussed. Stop-flow experiments effectively demonstrated the response and equilibrium time differences between these two ionophore membranes