Glassy carbon electrode, voltammogram

Fig. 29. Cyclic voltanunograms of a p-POD (p-phenylene oxadiazole) film on a glassy carbon electrode. Voltammograms were measured in 0.1 m BU4NCIO4 in acetonitrile with a scan rate of 10 mV/sec. Curve a is the first cycle and curve b is the sixth cycle.

Eig. 7. CycHc voltammograms for the reduction of 1.0 mAf [2,2 -ethylene-bis(nitrilomethyHdyne)diphenolato]nickel(II) in dimethyl formamide at a glassy carbon electrode, in A, the absence, and B and C the presence of 2.0 and 5.0 mAf 6-iodo-l-phenyl-l-hexyne, respectively (14). 

Fig. 17. Cyclic voltammogram of the water-soluble Rieske fragment from the bci complex of Paracoccus denitrificans (ISFpd) at the nitric acid modified glassy carbon electrode. Protein concentration, 1 mg/ml in 50 mM NaCl, 10 mM MOPS, 5 mM EPPS, pH 7.3 T, 25°C scan rate, 10 mV/s. The cathodic (reducing branch, 7 < 0) and anodic (oxidizing branch, 7 > 0) peak potentisds Emd the resulting midpoint potential are indicated. SHE, standEU d hydrogen electrode.

Figure 2. Cyclic voltammograms of ferrl-/ ferro-cyanlde couple at an activated glassy carbon electrode at scan rates of a) 20, b) 50, and c) 100 mV s . See text for details.

Figure 3. Cyclic voltammograms of ascorbic acid at a freshly polished, active (a) and a deactivated (b) glassy carbon electrode surface. See text for details.

Figure 17.12 Direct electrocatal3ftic oxidation of D-fnictose at a glassy carbon electrode painted with a paste of Ketjen black particles modified with D-fructose dehydrogenase from a Gluconobacter species. The enzyme incorporates an additional heme center allowing direct electron transfer from the electrode to the flavin active site. Cyclic voltammograms were recorded at a scan rate of 20 mV s and at 25 + 2 °C and pH 5.0. Reproduced by permission of the PCCP Owner Societies, from Kamitaka et al., 2007.

Since model compounds reveal well-defined cyclic voltammograms for the Cr(CNR)g and Ni(CNR)g complexes (21) the origin of the electroinactivity of the polymers is not obvious. A possible explanation (12) is that the ohmic resistance across the interface between the electrode and polymer, due to the absence of ions within the polymer, renders the potentially electroactive groups electrochemically inert, assuming the absence of an electronic conduction path. It is also important to consider that the nature of the electrode surface may influence the type of polymer film obtained. A recent observation which bears on these points is that when one starts with the chromium polymer in the [Cr(CN-[P])6] + state, an electroactive polymer film may be obtained on a glassy carbon electrode. This will constitute the subject of a future paper. 

Figure 3.59 Cyclic voltammogram of a glassy carbon electrode immersed in N2-saturated aceto-nitrile/0.2M tetraethylammonium tetrafluoroborate containing 5 x 10 3 M Re(dmbpy)(CO)3Ci, The scan rate is 100mVs 1. From Christensen et at. (1992).

FIGURE 13.2 Typical cyclic voltammogram of Prussian blue-modified smooth (mirrored glassy carbon) electrode 0.1 M KC1, 40mV s 1. 

Figure 1. Cyclic voltammograms in MeCN(0.1M tetra-ethylammonium perchlorate) for the oxidation of (a) a copper electrode, (b) 3 mM "OH at a glassy carbon electrode, (c) 0.5 mM "OH at a copper electrode, and (d) 3 mM "OH at a copper electrode. Scan rate, 0. IV s"1 electrode area, 0.08 cm2 copper electrode prepared by electroplating Cu(C104) onto a glassy carbon electrode (GCE). ...

Figure 8 Cyclic voltammograms recorded at a glassy carbon electrode in solution of [(jx-C5H5)Fe(CO)2]2 in (a) MeCN (b) CH2Cl2. Supporting electrolyte [NBu4][PF6], Scan rate 0.25 Vs l...

Cyclic voltammogram recorded at a glassy carbon electrode in a MeCN solution of the 16-metallocene complex illustrated in the scheme. Scan rate 0.1 V s... 

Figure 27 Cyclic voltammograms recorded at a glassy carbon electrode in a CH2Cl2 solution of [Cu2(N3)]2+ (a) under dinitrogen atmosphere (b) after bubbling of dioxygen and subsequent bubbling of dinitrogen...

One final issue remains to be resolved Of the portion of the AEpi that is due to resistance, what part is caused by solution resistance and what part is caused by film resistance To explore this issue we examined the electrochemistry of a reversible redox couple (ferrocene/ferricinium) at a polished glassy carbon electrode in the electrolyte used for the TiS 2 electrochemistry. At a peak current density essentially identical to the peak current density for the thin film electrode in Fig. 27 (0.5 mV see ), this reversible redox couple showed a AEpi of 0.32 V (without application of positive feedback). Since this is a reversible couple (no contribution to the peak separation due to slow kinetics) and since there is no film on the electrode (no contribution to the peak separation due to film resistance), the largest portion of this 0.32 V is due to solution resistance. However, the reversible peak separation for a diffusional one-electron redox process is —0.06 V. This analysis indicates that we can anticipate a contribution of 0.32 V -0.06 V = 0.26 V from solution resistance in the 0.5 mV sec control TiS2 voltammogram in Fig. 27. 

Figure 3.23 Cyclic voltammogram for a single-stranded DNA solution at the bare (A) and CNT (B) glassy carbon electrodes. Accumulation, 1 min at 0.2 V. Scan rate, 50mV/s. Measurements performed in 0.5 M acetate buffer (pH 5.9). Reprinted with permission from Ref [158]. Copyright, 2003, The Royal Society of Chemist. ...

Fig. 12 Cyclic voltammogram of [Mn202(phen)4] + in pH 4.5 phosphate buffer at an activated glassy carbon electrode i = 0.1 V s (reprinted with permission from Ref 97, Copyright 1992 American Chemical Society).

Fig. 35 Cyclic voltammograms for the electrocatalytic oxidation of NADPH by 2 10 M P2W16V2, in pH 8 buffer (50 mM TRIS + 0.5 M Na2S04 + H2SO4) the scan rate was 2 mV s , the working electrode was glassy carbon (3 mm diameter disk), the reference electrode was SCE. (a) The excess parameter values for NADPH were y = 10 and y = 20 respectively (b) Comparison of the catalytic process (y = 20) by P2W16V2 with the direct oxidation of NADPH on the glassy carbon electrode (taken from Ref 185).

Fig. 6 Representative examples of the steps involved in the convolution analysis approach to obtaining the potential dependence of the heterogeneous rate constant. From top to bottom (a) background-subtracted cyclic voltammograms as a function of scan rate (left to right 0.5, 1, 2, 5, lOVs " ) (b) corresponding convolution curves (c) corresponding potential dependence of logkhet obtained using equation (25). Figures shown are for the reduction of (MeS)2 in DMF/0.1 M TBAP at a glassy carbon electrode.

Corresponding to a cyclic voltammogram (CV), recorded at a glassy carbon electrode (GCE) immersed into a 1.0 mM Cu + solution in acetic acid/sodium acetate... 

This is illustrated in Fig. 2.4, where the deconvolution of differential pulse voltammograms at the glassy carbon electrode in the ethanol extract from two commercial inks are shown. Samples were taken from paper fragments of 0.10 mg immersed for 10 min in a 50 50 (v/v) ethanol 0.50 M aqueous acetate buffer (pH 4.85) solution. 

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