Determination of Superoxide radicals in aqueous solutions of C₆₀ and its derivatives

The aqueous solutions of C₆₀₂ of and C₆₀ NCH₂CONH₂ ( N-acetamide 1, 2-dihydro-1, 2-aza-fullerene [C₆₀]) were prepared by the polyvinylpyrrolidone method. Using lucigenin as the photosensitive probe for the superoxide radicals, the superoxide radicals in the solution of C₆₀ and its five derivatives (including C₆₀NCH₂CONH₂,C₆₀(OH)_n and three C_60/70 acrylic acid copolymers) were determined under both irradiation and non-irradiation by photon calculator. The effect of C₆₀(OH)_n on the superoxide radicals was also studied. The results show that the superoxide radicals can be generated only in the C₆₀ solution under irradiation, while C₆₀(OH)_n has the activity of reducing the superoxide radicals in aqueous solution, suggesting that the superoxide radicals are involved in the photosensitive reaction of C₆₀, but not in those of its derivatives.