The adsorption of mixtures of alkyl thiol surfactants on the Au(111) surface as well as on icosahedral gold nanocrystals (NCs) was investigated by molecular simulation. We compared the molfraction of each surfactant type on the gold structure with the molfraction of each surfactant type in the surrounding bulk solvent. For alkyl thiol surfactants with 1 to 4 carbon atoms difference, we found that, in contrast to the (111) surface, the adsorption selectivity on a NC is almost identical to that in the solvent. © 2007 Elsevier B.V. All rights reserved.