The transport of Hg2+ ions through a chloroform bulk liquid membrane containing tetrathia-12-crown-4 (TT12C4) as a specific ion carrier was studied, Mercury ion is quantitatively transported across the liquid membrane in the presence of ethylenediaminetetraacetic acid (EDTA) as a suitable stripping agent in the receiving phase, the amount of mercury transported across the liquid membrane after 2 h is 99.0 +/- 1.0%. Excellent mercury ion selectivities relative to a wide variety of alkali, alkaline earth, transition and heavy metal ions were observed. (C) 2002 Elsevier Science B.V. All rights reserved.