The diffusion coefficient (D) of the 1:1 gamma-cyclodextrin (gamma-CD)/C-60 complex was determined in aqueous electrolytes using a nitrogen-incorporated tetrahedral amorphous carbon (taC:N) rotating disk electrode and the hydrodynamic modulation technique. requiring no knowledge of concentration. Thr value of 1.3 x 10(-6) cm(2)/s at 20 degrees C is consistent with best estimates from Levich plots and with the expected molecular dimensions of these inclusion complexes.