A simple solvent extraction study for thallium has been conducted based on the extraction of thallium as a chlorocomplex (tetrachlorothallate (111) anion) with tribenzylamine. Radiolabelled Tl (111) was used to study the extraction behavior of thallium. The beta activity of the extracted ion-association complex has been monitored using liquid scintillation counting and Geiger Muller counter. The effect of various diluents such as toluene, chloroform and isobutylmethylketone (MIBK) were studied. The extraction efficiency was 95% when chloroform and MIBK were used as diluents for tribenzylamine at an overall concentration of 0.25 mol dm(-3) NaCl and 0.5 mol dm(-3) H2SO4. The phenomenon of severe chemical quenching was observed with chloroform as the diluent. The recovery of thallium was found to be 95% at varying concentrations ranging from 5 to 20 mu g ml(-1) Tl (III) with a relative standard deviation of 2.5%. (c) 2005 Elsevier B.V. All rights reserved.