Differential pulse voltammetry

Differential pulse voltammetry is a kind of electrochemical measurement categorized as pulse voltammetry. Other types of pulse voltammetry are square pulse voltammetry, differential pulse voltammetry, and normal pulse voltammetry. These measurements can be used to study the redox properties of extremely small amounts of chemicals because their feasures are mainly the following two points:

(1) In these measurements, the effect of the charging current can be minimized,so high sensitivity is achieved. (2) Faradaic current is extracted, so electrode reactions can be analyzed more precisely.

Differenetial pulse voltammetry has these characteristic properties:

(1) Reversible reactions show symmetrical peaks, and irreversible reactions show asymmetrical peaks. (2) The peak potential is equal to E_1/2^r-ΔE in reversible reactions, and the peak current is proportional to the concentration. (3) The detection limit is about 10^-8 M.

The system of this measurement is usually the same as that of cyclic voltammetry. The potential between the working electrode and the referenece electrode is changed as pulse from an initial potential to an interlevele potential and remains at the interlevel potential for about 5-100 ms; then it changes to the final potential, which is different from the initial potential. The pulse is repeated, changing the final potential, and at a constant differenece is kept between the initial and the interlevel potential. The value of the current before and after the pulse are sampled and their differeneces are plotted versus potential.