Graphite impurities cause the observed 'electrocatalysis' seen at C60 modified glassy carbon electrodes in respect of the oxidation of l-cysteine

The recently reported claims of electrocatalysis using C60 film modified glassy carbon electrodes [W.T. Tan, A.M. Bond, S.W. Ngooi, E.B. Lim, J.K. Goh, Anal. Chim. Acta 491 (2003) 181] for the oxidation of l-cysteine are questioned. We show that C60 itself is not electrocatalytic at the potentials concerned but rather it is likely that graphite impurities in the C60 material used by Tan et al. that provide their observed 'electrocatalysis'.