Current location: JICS Archive > Vol. 4 > No. 1 > Articles : 4

An Active Transport Mimetic System Based on Thioctic Acid as Carrier for Alkaline Earth Metal Ions

R. Zugle^a,* J. Kambo-Dorsa^a and V.P.Y. Gadzepco^b

^aDepartment of chemistry, University of Cape Coast, Cape Coast, Ghana
^bCentral University College, Accra, Ghana

Liquid membranes incorporating thioctic acid as a carrier to mimic an active transport system for alkaline earth metals has been described. A transport cell, operating on the same principle as the Schulman Bridge was used. It has been demonstrated that such a system is capable of transporting alkaline earth metals against a proton gradient, as driving force. The potential of thioctic acid to complex and transport these metal ions particularly Mg²⁺, Ca²⁺, and Ba²⁺ was verified. Furthermore, this transport phenomenon was extended to some different barium salts (Cl^-, Br^-, NO₃^-, and SCN^-) to determine the effect of nature of anion on the transport of the Ba²⁺ ions. The order of the transport rate was found to be Ba²⁺ > Ca²⁺ > Mg²⁺ which is inconsistent with the stability of coordination to the carboxyl group. The rate of transport of Ba²⁺ ions were found to decrease with the anion type in the order SCN^- > Br^- > NO₃^- > Cl^- which is related to the extent of hydration of the anions.

Keywords: Active transport, Liquid membrane, Alkaline earth, Thioctic acid, Anion type