Direct Electrochemical Detection of C 60 in Solution by Steady‐State Voltammetry at Microelectrodes

The direct electrochemical detection of C 60 in solution was investigated by steady-state voltammetry at Pt microelectrodes. Highly reproducible voltammograms were obtained in 1,2-dichlorobenzene with 0.050 M tetra-n-butylammoniumhexafluorophosphate as supporting electrolyte, using a freshly polished electrode surface. Linear correlation between the limiting current of the first reduction step and the C 60 concentration was excellent (r = 0.9999) for concentrations in the range of 1.0 x 10 -5 to 1.0 x 10 -3 M. The detection limit of C 60 was 8.2 x 10 -6 M (5.9 mg/L). At higher concentrations (up to 3.0 x 10 -2 M), the measured limiting currents were up to 6.6% below those expected by extrapolation of the linear domain. The technique was applied to the determination of the solubility of C 60 in toluene, dichloromethane, trichloromethane, tetrahydrofuran, and dimethylformamide, and for the estimation of the total fullerene content of a commercial carbon soot, by the standard addition method.