Differential double pulse voltammetry

Fig. 3.56. Sampling scheme of differential double-pulse voltammetry.

They are applicable to electrodes of any shape and size and are extensively employed in electroanalysis due to their high sensitivity, good definition of signals, and minimization of double layer and background currents. In these techniques, both the theoretical treatments and the interpretation of the experimental results are easier than those corresponding to the multipulse techniques treated in the following chapters. Four double potential pulse techniques are analyzed in this chapter Double Pulse Chronoamperometry (DPC), Reverse Pulse Voltammetry (RPV), Differential Double Pulse Voltammetry (DDPV), and a variant of this called Additive Differential Double Pulse Voltammetry (ADDPV). A brief introduction to two triple pulse techniques (Reverse Differential Pulse Voltammetry, RDPV, and Double Differential Triple Pulse Voltammetry, DDTPV) is also given in Sect. 4.6. 

Equation (4.77) corresponds to the normal mode of Differential Double Pulse Voltammetry for which the duration of the second applied pulse is not restricted as in the case of DDPV [35]. From this equation, the expression of the current A/dndpv at very negative and positive potentials valid for any electrode geometry can be directly obtained,... 

In this section, the analytical expressions given by Eqs. (4.171) and (4.172) are applied to differential double pulse voltammetry (DDPV) [63,64]. In this technique the duration of the second pulse is usually much shorter than that of the first i > 50 x t2. Under these conditions, fc,(j + r2,<7c) /g(ti, <7g) so equation for A ddpv simplifies to ... 

In the case of DMPV (see Scheme 7.2), the treatment followed in Sect. 4.2.4.1 for Differential Double Pulse Voltammetry (DDPV) for one and two polarizable interfaces can be used because the equilibrium is quickly reestablished during the longer period Therefore, the peak potential of the DMPV curves when the current is plotted versus the index potential is... 

With respect to the peak potentials, their value are independent of all the technique parameters (including the pulse amplitude) and it is corroborated that it coincides with the peak potential in Differential Double Pulse Voltammetry (DDPV) and Differential Multipulse Voltammetry (DMPV). So, by imposing the condition dy/ vw/dE = 0 in Eq. (7.65), the three following roots are obtained in terms of K [49] ... 

Appendix G. Application of Two Potential Pulses to a Non-reversible Charge Transfer Differential Double Pulse Voltammetry and Reverse Pulse Voltammetry... 

Solution for Spherical Electrodes in Differential Double Pulse Voltammetry... 

Lane, R. F., Hubbard, A. T., and Blaha, C. D., 1976a, Differential double-pulse voltammetry at chemically modified platinum electrodes for in vivo determination of catecholamines, Anal. Chem. 48 1287-1293. 

Differential Double Pulse Voltammetry (DDPV), where the length of the second pulse (t2) is much shorter than the length of the first pulse (t/), t//t2 = 50-100 (Fig. 2.36a), which leads to very high sensitivity. Differential Double Normal Pulse Voltammetry (DDNPV) is where both pulses have similar durations tj x t2 (Fig. 2.36b). 

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