“…The separation of thallium (I) has been intensively studied through the formation of ion-pair complex with basic triphenymethane dye [11], with cryptand 2,2,2, erythrosine [12] and benzo-15-crown-5 [13], 18-crown-6 [14] and dibenzo-24-crown-8 [15] or 12-crown-4 [16] with picrate. The complexation reaction between Tl (I) and crown ethers in organic solvents at 25 • C with stoichiometry of 1:1 has been studied and the best crown ether was found to be DCH-18-crown-6 [17].…”