The formation of an inclusion complex between the sulfonated beta-cyclodextrin (S beta-CD) with dopamine (DA) was confirmed using UV-vis measurements and NMR methods. It was also established that a 1:1 complex was formed between the S beta-CD and the DA, where the inclusion occurred predominantly through the aromatic ring of the DA and the hydrophobic CD cavity. The results also suggest that a change in the anion, of supporting electrolyte, had an influence on the DA-S beta-CD complexation while no change was observed for the cation. (C) 2011 Elsevier B.V. All rights reserved.