Relation of Plasticizers and Ionophore Structures on Selectivities of Lithium Ion-Selective Electrodes

Abstract Measurements were made of selectivity coefficients for lithium ion-selective electrodes containing five different lipophilic diamide ionophores with combinations of three different backbones and three different sidechains, in PVC membranes containing o-NPOE plasticizer. Comparing with results for similar membranes containing tris(2-ethylhexyl)phosphate plasticizer revealed that use of o-NPOE plasticizer enhances the selectivity for lithium with respect to sodium only for ionophores with the sidechain, irrespective of the backbone.