Fullerene purification
Fullerene purification is the process of obtaining a fullerene compound free of contamination. In fullerene production mixtures of C60., C70 and higher homologues are always formed. Fullerene purification is key to fullerene science and determines fullerene prices and the success of practical applications of fullerenes. The first available purification method for C60 fullerene was by HPLC from which small amounts could be generated at large expense.
A practical laboratory-scale method for purification of soot enriched in C60 and C70 starts with extraction in toluene followed by filtration with a paper filter. The solvent is evaporated and the residue (the toluene-soluble soot fraction) re-dissolved in toluene and subjected to column chromatography. C60 elutes first with a purple color and C70 is next displaying a reddish-brown color.