Determination of sulfur as an impurity in commercial C60, fullerene soot and sublimed C60 polycrystals by INAA

By using instrumental neutron activation analysis (INAA) it has been shown that commercial C-60 products contain considerable amounts of sulfur impurity. This element could be found in all C-60 samples of three main producers which, in fact, necessitated to study the capabilities of the INAA sulfur determination in more detail. Although only one sample did contain a surprisingly high sulfur amount of about 8%, even the sublimed C-60 sample showed a sulfur content of about 0.02%.