Direct electrochemical detection of C60 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.