High Resolution NMR Studies of Lithium and Sodium lons at the Membrane Interface

Abstract

High resolution NMR spectra of lithium-6, lithium-7 and sodium-23 in a liquid crystalline mesophase consisting of sodium decylsulfate, lithium sulfate, decanol and water have been recorded. From the quadrupole splittings of the two lithium isotopes, a ratio of the quadrupole moment (Q) of ⁷Li/⁶Li equal to 49 ± 1 was obtained. By comparing the temperature dependence of the quadrupole splittings of ⁶Li, ⁷Li and ²³Na in the same mesophase, it is apparent that lithium and sodium ions interact differently with the polar head group of the mesophase. The implication of this difference is discussed.