However, there appears to be a weak correlation of k 0 and C dl with larger k 0 values being associated with data sets having higher C dl values. There also appears to be a weak correlation between k 0 and E 0 , with the more positive E 0 values coinciding with the larger C dl values. One needs to be careful not to over interpret the significance of weak correlations, as other non-quantified parameters also can be operative. However, a larger capacitance current caused by a larger activation of the glassy carbon surface (more surface functionality) may be expected to increase the rate of an inner sphere process, like the [Fe(CN) 6 ] 3-/4-one probed in this work. The origin of the weak correlation of k 0 and E 0 is more problematical.