A series of tripodal receptors that are different from each other in their end groups were synthesized. The extraction ability and the transport rate of these receptors were evaluated for transition metal ions (Fe3+, Ni2+, Cu2+, Zn2+ and Hg2+). The receptor bearing pyridyl nitrogens extracted Hg2+ from a buffered aqueous medium containing a mixture of metal ions and transported it into an organic phase with a complete selectivity over the other metal ions. This receptor was effectively used for transporting Hg2+ from aqueous buffered source phase to aqueous receiving phase through a chloroform membrane. (c) 2009 Elsevier B.V. All rights reserved.