Voltammograms DPVs differential pulse

Fig. 6 Plots of cyclic and differential pulse voltammograms for bpz-linked species 43 and 44 in 0.1M dichloromethane solution of (Bu4N)(PF6). The scan rates are lOOmVs-1 for CV and 20 mV s 1 for DPV...

As mentioned, DPV is particularly useful to determine accurately the formal electrode potentials of partially overlapping consecutive electron transfers. For instance, Figure 40 compares the cyclic voltammogram of a species which undergoes two closely spaced one-electron oxidations with the relative differential-pulse voltammogram. As seen in DPV the two processes are well separated. 

Figure 3.11 Differential pulse voltammograms (DPVs) for guanine at bare glassy carbon, SWNT modified glassy carbon and bamboo-modified glassy carbon. DNA cone, 0.4 mgmL (b) the corresponding DPV plots observed in (a) but with background subtraction. The signal gene rated from...

Always monitor the electrical transduction of DNA damage by differential pulse voltammetry (DPY). Between recording voltammo-grams always keep the working electrode at a standby potential of OY. Before recording a voltammogram use an equilibration time of 5 s. The experimental conditions for DPV are as follows pulse amplitude 50 mV, pulse width 70 ms and scan rate 5 mV s 1. 

Figure 10 Potential waveforms for normal pulse (NPV) and differential pulse voltammetry (DPV) displaying potential versus time (b), and a typical normal pulse and differential pulse voltammogram plotting current versus potential (a)...

Fig. 14.25 Automated evaluation of a Ni porphyrin44 (a) Differential pulse voltammograms (DPVs) recorded for different NO concentrations (b) Peak current measured from DPVs for five NO concentrations recorded in 22 sequential measurements in a microtiter plate (c) Resulting calibration plot (n = 22)...

Fig. 9. Typical differential pulse voltammogram (DPV) for the oxidation signals of Au during the sandwich assay to 38pmol of CF-T (A) and sandwich assay without CF-T used as control (B). Conditions hybridization time, 15 min hybridization temperature, 42°C amount of paramagnetic beads, 50gg electrooxidation potential, +1.25V electrooxidation time, 120s DPV scan from +1.25 to OV, step potential 10 mV, modulation amplitude 50 mV, scan rate 33.5 mV/s, nonstirred solution.

Figure Bl.28.5. Applied potential-time waveforms for (a) normal pulse voltammetry (NPV), (b) differential pulse voltammetry (DPV), and (c) square-wave voltammetry (SWV), along with typical voltammograms obtained for each method.

Single-fiber sensors and catheter-protected sensors can operate in an amperometric or voltammetric mode. In both methods a current proportional to NO concentration is measured. Of the several voltammetric methods available, differential pulse voltammetry (DPV) is most suitable for the measurement of NO. In DPV, a potential modulated with rectangular pulses is linearly scanned from 0.4 to 0.8 V. The resulting voltammogram (alternating current versus voltage plot) contains a peak due to NO oxidation. The peak current should be observed at a potential of 0.63-0.67 V which depends on the pulse amplitude. This potential is the characteristic potential for NO oxidation on Nafion coated porphyrinic sensor. 

Oxidation of NO on classical conductive materials such as noble metals (platinum, gold, etc.) or carbon, which are used as electrodes, produces a relatively low current at neutral pH. This is due to a strong absorption of NO to the electrode surface and a slow rate of electron transfer between NO and the electrode. Typical differential pulse voltammograms (DPV) of NO on carbon liber covered with Nafion, and carbon fiber covered with porphyrinic film and Nafion are shown in Fig. 3. There is about a 190 mV difference between the oxidation potential of NO on carbon fiber and porphyrinic film. A concentration of 0.1-pM NO produces a very small current on the carbon fiber electrode operating in the DPV mode (Fig. 3a). However, this same carbon fiber covered with a layer of polymeric porphyrin produces a much larger current (Fig. 3b) for NO oxidation. The current generated on polymeric porphyrin is mass transport controlled and is linearly proportional to the concentration of NO. The linearity is observed over four orders of magnitude of NO concentration [45]. 

Due to space limitations, we do not discuss in detail the potential excitation function used in differential pulse voltammetry (DPV), which is a technique developed before SWV and uses the same principles for removal of background currents and yields voltammograms in many ways similar to those obtained with SWV. DPV is, however, an inherently slower technique, as scan rates are usually limited to a few millivolts per second. However, neither of these techniques provides a direct means to quantify any changes in the stability of a supramolecular complex or the motions in a molecular machine. 

Figure 9.50 Differential pulse voltammogram (DPV) recorded on 1.74 nm Si nanoparticles. The reversible peaks near +0.09 and -0.7 V are attributed to the electron transfer through HOMO and LUMO of Si NPs. Reprinted with permission from reference (139). Copyright 2002, AAAS.

Fig. 36 Differential pulse voltammograms (DPV). (a), s -BU[Thi]2 and unstacked model Thi (b) s -BU[Th3]2 and unstacked trimer Th3 (c) plot of oxidation potentials of linear (Thn) and stacked analogs (s -BU[Thn]2) (from [149])...

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