A new adsorbent for preconcentration and separation of silver ion from aqueous sample solutions has been reported. Sodium dodecyl sulfate (SDS), as a surfactant, makes admicelle on the surface of substrate gamma-alumina, which allows the metal complexing agent, 2-mercaptobenzothiazole (MBT), to be immobilized in its hydrocarbon cores. This assemble, as a chelating adsorbent, has made the separation and preconcentration of silver ion possible. Factors influencing the adsorption of mug/ml levels of silver ion concentration from solutions by the adsorbent have been investigated. A preconcentration factor of 100 has been found. An aqueous solution containing thiourea has been used in order to selectively desorb the adsorbed silver ion from the surface of the adsorbent, which is a new stripping technique that is introduced in solid-phase extraction methods. No serious interferences have been observed due to the presence of another species in the sample. The separation selectivity of the adsorbent for other cations was studied. To improve this, EDTA was added to the source solution before applying to the column. The method is simple and inexpensive. (C) 2003 Elsevier Science B.V. All rights reserved.