Voltammogram for mixtures

Fig. 3.1 Stripping voltammograms for mixtures containing increasing levels of cadmium and lead, 10-80 tg/l (a — h) in 0.1 M acetate buffer (pH 4.2). Deposition for 2min at —l.OV vs. Ag/AgCl/KCl(sat.), using unstirred solutions /= 45 Hz, sw = 20 mV and AE = 6 mV (reprinted from [46] with permission)...

A linear-potential scan hydrodynamic voltammogram for a mixture of Le + and Le + is shown in the figure, where and... 

Figure 6 compares voltammograms for P(EO)9(ZnCl2)08 CsCl which contains a mixture of ZnClj and ZnCl4 and for a zinc triflate derivative [95], The metal desposition process can be written as Eq. (6),... 

Fig. 4.5 Square-wave voltammograms for commercial Brazilwood (a) and logwood (e), and mixtures of both pigments containing 50% (b), 75% (c), and 85 % (w/w) (d) of Brazilwood, attached to paraffin-impregnated graphite electrodes. Electrolyte ...

Fig. 4.6 Variation of the peak currents for peaks at +0.20 (squares) and at +0.65 V (rhombs) with the percentage of Brazilwood in square-wave voltammograms for Brazilwood plus logwood mixtures in contact with a phosphate buffer. Conditions are as in Fig. 4.5. Here, identical amounts of sample were transferred to the parafiSn-impregnated graphite electrode...

Fig. 4.16 Square-wave voltammograms for (a) alizarin (15.72%) + morin (7.16%) -I- silica (77.12%) and (b) alizarin (19.03%) + purpurin (8.30%) -I- raorin (12.48%) -I- silica mixtures (60.19%). Electrolyte 0.50M sodium acetate buffer, pH 4.90. Potential step increment 4 mV square-wave amplitude 25 mV frequency 15 Hz [241]...

Evans and. Gilicinski [61b] used cyclic voltammetry assisted by a simulation method to determine the rate constants for a homogeneous electron-transfer reaction Oxy + Red2 Red + Ox2. They measured cyclic voltammograms for the mixtures of Ox and Ox2. If the above reaction does not occur, the reduction-reoxidation peaks... 

Record the hydrodynamic voltammograms for a mixture of H2O2 and AsA in order to determine the optimal detection potential. Injection and separation is performed as described in Section 48.4. Injection is carried out by applying a voltage of + 2000 V for 10 s. + 2000 V is applied for separation using 50 mM Tris-based buffer pH 9.0. The detection potential is varied between 0 and +0.9 V. Thus, hydrodynamic curves of H202 and AsA have to reach a plateau where the optimal potential is chosen. 

Fig. 9.6 Cyclic voltammogram for aluminum deposition on Au (111) in the upper phase of the biphasic mixture of AICI3/[Pyi, 4] TFSA at room temperature. Scan rate 10 rnVs 1.

Fig. 6.2. Voltammogram for a reversible system where the solution contains O and R. Example a mixture of Fe(II) and Fe(III) at a platinum rotating disc...

Fig. 9. Effect of solution pH on the redox behavior of an Ru02 aqueous solution interface. (— -), From work with an Ru02/Ti02 film [209]. The upper lines are for the Ru(IV)/Ru(VI) transition as obtained from voltammograms for pure RuOz (on Ti) in a range of borate (pH > 8) and phthalate (pH < 8) buffer solutions O and refer to the cathodic and anodic peak maxima respectively. (- -), Variation of the half-wave potential for benzaldehyde oxidation (O.lmoldm-3, scan rate = 1.5mVs 1) on pure Ru02 in buffered 10% f-butanol in water mixtures. The voltammograms outlined on the left and right for Ru02 in acid and base, respectively [207],...

Ordinarily, the electroactive species in a mixture behave independently of one another at a voltammetric electrode a voltammogram for a mixture is thus simply the summation of the waves for the individual components. Figure 23-9 shows the voltammograms for a pair of two-component mixtures. The half-wave potentials of... 

Figure 23-9 Voltammograms for two-component mixtures. Half-wave potentials differ by 0.1 V in curved and 0.2 V in curve B.

For the analysis, three series of synthetic solutions with six concentrations each in the range of [5.0, 35] mM for Cys and Tyr, and [2.0, 21] mM for Trp were prepared. These concentrations were studied at two levels 10 and 25 mM for Trp and Cys 5.0 and 34 mM for Tyr. The set of mixture solutions for each analyte was 24, obtained by varying the concentration of the corresponding analyte in its specified range in each of the 4 possible combinations for the level of the two remaining analytes. With this procedure, the total set of mixture solutions and recorded voltammograms for the three analytes is 72. 

Figure 3 shows a cychc voltammogram for compound 3H at a low-scan rate (see footnote 1). In all cases, starting with a cathodic scan, no reduction waves appear in the first scan, so neither l-chloro-2,4,6-trinitrobenzene (the Sn product), nor 1,3,5-trinitrobenzene (the Sn product), are initially present in the reaction mixtures. Figure 3a shows that, upon starting with an anodic scan, two well-defined waves at 0.68 V and 1.24 V are observed. When the anodic scan is followed by a cathodic scan, two waves, at 0.53 V and 0.56 V, are observed. These reduction waves correspond to l-chloro-2,4,6-trinitrobenzene (the Sn product) and 1,3,5-trinitrobenzene (the Sn product), respectively [23, 40]. 

Fig. 2 Typical stripping voltammogram for a mixture containing 10 M zinc, cadmium, lead, and copper.

Figure 5.2 Cyclic voltammograms for the redox processes, (a) oxidation of 3-(pyrrol-l-yl)propanesulfonate ca 7mM) in MeCN-Bu4NBp4 electrolyte at a Pt electrode (A = 1.8mm ), scan rate lOOmV/s, / =10p.A (b) oxidation of a 1 1 mixture of pyrrole and 3-(pyrrol-l-yl)propanesulfonate under the same conditions, i = 20p.A (c) redox reaction of poly(pyrrole-co-(3-(pyrrol-l-yl)propanesulfonate)) in MeCN-O.lM LiC104 electrolyte, i = 5 p.A. (Chemical Communications, 1987, 621, N. S. Sundaresan, S. Basak, M. Pomerantz, J. R. Reynolds. Reproduced by permission of The Royal Society of Chemistry.)...

Figure 17 (a) Voltammogram for the redox reaction of ferrocene in the water-in-supercritical CO2 microemulsion system, (h) Voltammogram for the redox reaction of TMPD in the water-in-superciitical CO2 microemulsion system, (c) Voltammogram for the redox reaction of ferrocene in the supercritical C02-ethanol mixture system. Scan rate 200 mV s. (From Ref. 15.)... 

Diamond electrodes were oxidized by applying a potential of 2.6 V vs. SCE for 75 minutes in 0.1 M KOH. At as-deposited diamond, the oxidation potentials for AA and UA were similar. The detection of UA in the presence of AA required chromatographic separation. The oxidation potential for AA shifted to more positive values as compared to that of UA at the oxidized diamond electrode, thus minimizing interference from AA during the detection of UA in acidic media. Fig. 12.4 shows the cyclic voltammogram for a mixture of UA and AA at as-deposited and oxidized BDD electrodes. UA was detected with simple chronoamperometry with no requirement of complicated procedures. These authors have successfully determined UA in diluted urine samples (by a factor of 10000), and the electrodes have shown stability for about 3 months. 

Fig. 12. 4. Cyclic voltammograms for a mixture of 0.2 mM UA and 1 mM AA at as deposited(dashed line) and oxidized (solid line) diamond electrodes in 0.1 M HCIO4 solution. 

Figure 8.9 Polarization curves for a PtSn/C catalyst recorded by a rotating disk electrode in 0.5 M H2SO4 saturated with either pure hydrogen, a H2/2% CO mixture, and pure CO (the arrow points to the onset of CO oxidation) at 60 °C with 1 mV/s and 2500 rev/min the dashed curve is the cyclic voltammogram (in arbitrary units) in an argon-purged solution at 60 °C with 50 mV/s. (Reprinted with permission from Aienz etal. [2005]. Copyright 2005. Elsevier.)...

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