Faradaic impedance spectra

Figure 2.23 Faradaic impedance spectra presented in the form of Nyquist plots, along with the electronic equivalent circuit of the electrified interface. (Reproduced with permission from Ref. 87.)...

Figure 3-5. (A) Assembly of reconstituted glucose oxidase on a PQQ-FAD monolayer linked to an Au-electrode. (H i Faradaic impedance spectra of the modified electrode at time intervals of reconstitution, (a) 0.1 h, (b) 0.25 h. (c) 0.5 h. (d) 1 h. (e) 2 h, (f) 4 h. Inset Interfacial electron transfer resistance of the modified electrode at time-intervals of reconstitution. (C) Cyclic voltammograms corresponding to the bioelectrocatalyzed oxidation of glucose, 80 mM, by the enzyme-functionalized electrode at time-intervals of reconstitution (a) 0 h, (b) 0.1 h, (c) 0.25 h, (d) 0.5 h, (e) 1 h, (f) 2 h, (g) 4 h. Inset Electrocatalytic currents transduced by the enzyme-modified electrode at time-intervals of reconstitution. Reproduced with permission from ref. 32. Copyright 2002 American Chemical Society.

Fe(CN)6] " as the redox label and impedance spectroscopy as the readout signal. (B) Faradaic impedance spectra upon analyzing different concentrations of neomycin B (a) 0 (b) 0.75 (c) 2 (d) 5 (e) 50 (f) 500 tiM. Inset Calibration curve corresponding to changes in the interfacial electron-transfer resistances upon analyzing different concentrations of neomycin B. (Reprinted with permission from De-los-Santos et al., 2007. Copyright 2006 American Chemical Society.)... 

Figure 13 (A) Faradaic impedance spectra of (a) the (17)-functionalized Au electrode, (b) after interaction of the sensing electrode with (18) (5 x ICf M, 15 min, 25°C), and (e) after interaction with the (19)-functionalized liposomes. Inset Faradaic impedance spectra of (a) the (17)-modifled electrode, (d) after interaction with (18a) (5x10 M), (e) after treatment with (19)-functionalized liposomes. All measurements were performed in a 0.1 M phosphate buffer (pH 7.2) in the presence of [Fe(CN)g] /[Fe(CN)g] (5 x lO"- M, 1 1) as a redox-probe. (B) Changes in the electron transfer resistance of the (17)-functionalized electrode upon treatment with the analyte DNA, (18), at different concentrations and upon the secondary amplification with the (19)-functionalized liposomes corresponding to the difference in the electron transfer resistance, AR, after amplification with the (19)-func-tionalized liposomes and the resistance of the (17)-functionalized electrode.

Figure 19 (A) Faradaic impedance spectra corresponding to (a) A bare An electrode, (b) The (26)-functionalized electrode, (c) After interaction of the sensing electrode with the analyte DNA, (27), 6.5 x M. (d) After treatment of the sensing electrode with the...

Figure 22 Faradaic impedance spectra corresponding to the biocatalytic transformations of nucleic acid-functionalized electrodes (a) The (29)-funetionalized electrode (b) after ligation of (30), 1 x 10 M, with the (29)-functionalized electrode in the presence of Ug-ase, 20 units, 37°C, 30 min (c) after hybridization of the resulting electrode with (31), 1 x 10 M, 2 h (d) after replication of the double-stranded assembly in the presence of dNTP, 1 X 10 M, and polymerase, 3 units, 37°C, 30 min (e) after scission of the resulting assembly with endonuclease, Cfo 1,10 units, 37°C, 1 h (f) after ligation of the resulting interface with (32), 6.5 x 10 M, in the presence of ligase, 20 units, 37°C, 30 min (g) after hybridization of the assembly with (31), 1 X 10 M, for 2 h.

Figure 26 shows the faradaic impedance spectra (in the form of Nyquist... 

Figure 26 Faradaic impedance spectra corresponding to (a) The (33)-modified electrode, (b) After hybridization with M13< DNA, 2.3 X 10 M. (c) After the polymerase-induced replication and formation of the double-stranded assembly for 45 minutes, (d) After the binding of the avidin-alkaline phosphatase conjugate to the surface, (e) After the biocatalyzed precipitation of (12) for 20 minutes in the presence of (11), 2 X 10 M, in 0.1 M Tris-buffer, pH = 7.2.

Figure 31 (A) Faradaic impedance spectra corresponding to (a) the (38)-modifled elec-...

Faradaic impedance spectroscopy investigation of Fe(CN)4 transport in P2VP brush-modified ITO. (a) Equivalent electronic circuit used to model physicochemical processes associated with the faradaic impedance spectra, (b) Typical impedance spectra (Nyquist plot), Im(Z) vs. Re(Z), for decreasing pH values (from a to g) Hne best fit to the equivalent circuitry, (c) Titration curve showing changes of the electron transfer resistance derived from (b) and fitted by (a) upon variation of the pH going in the (i) acidic then (ii) basic and (iii) acidic directions. (Adapted from Motornov, M., et al., ACS Nano, 2,41-52,2008.)... 

Figure 1.23 Schematic Faradaic impedance spectra presented in the form of a Nyquist piot.

FIGURE 18.4 Structure of the cross-linked polyelectrolyte gel membrane and the reversible change of the chemical stimuli-responsive membrane in the absence (a) and presence (b) of cholesterol, (c) Faradaic impedance spectra obtained for the membrane-modified electrode in the absence (i, iii) and presence (ii, iv) of cholesterol corresponding to the open and closed pores, respectively. Inset (c) The reversible changes of the electron transfer resistance, R , derived from the impedance spectra upon addition and removal of cholesterol. (Adapted with permission from Ref. [83]. Copyright 2007, American Chemical Society.)... 

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