Gold electrodes charge density

First cycle is considered on platinum and vitreous carbon whereas the second one is studied on a gold electrode. In the latter case, the reproducibility is better for the second cycle than for the first cycle and, with the exception of depilatory cream from Klorane, the charge density is the same on the two first cycles. 

Figure 3.13 Surface charge density on a gold electrode surface plotted versus the electrode potential for (dotted curve) 50mM NaF supporting electrolyte and (circles) mixed 7 3 DMPC-cholesterol bilayer spread from vesicle solution. Figure taken from [84]. 

At solid polarizable electrodes, the charge density on the electrode can be measured directly using chronocoulometry [11]. This has been applied successfully to the study of molecular adsorption at single crystal gold electrodes. As discussed above, a reference potential E is chosen at which molecular adsorption is absent. The potential of the polarizable electrode is then stepped to a new value f ,- and the current transient which results is recorded. By integrating this transient, one obtains the change in charge density between the two potentials ... 

Figure 4.2 Impedimetric detection of DNA oligonucleotides. Sensor preparation as in Figure 4.1. The accessibility of the gold surface for ferri-/ferrocyanide depended on the amount of negative charge accumulated on the electrode surface. DNA hybridization increased the negative charge density and yielded increased charge transfer resistance as measured by impedance spectroscopy.

FIG. 8. Frequency shift versus surface charge density on gold and silver electrodes in 0.1 M solution of LiC104 in water (a) and in butanol (b). (Fig. 8a from Ref 98.)... 

FIG. 11. The frequency shift versus the surface charge density on gold electrode in 0.1 M LiC104 without (closed circles) and with (open circles) uracil (4 mM). 

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