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Sensor pulsed techniques: SWV, DPV & NPV – Electroanalysis Electrochemistry Sensor – Application Note 67

Latest updated: May 6, 2020

Abstract

This note introduces three of the most common pulsed techniques used in electrochemistry, which are available in EC-Lab. Pulsed techniques are mainly used to detect reactants at very low concentrations. In some conditions, they can be preferred over other voltammetric techniques, such as cyclic voltammetry on a static or a rotating electrode.

 

Introduction

The pulse voltammetric techniques are electroanalytical techniques mainly used to detect species of very small concentrations. (10-6 to 10-9 mol L-1). They were developed to improve voltammetric polarography experiments, in particular by minimizing the capacitive (charging) current and maximizing the faradaic current. The polarography was invented by Prof. Heyrovský (for which he won a Nobel prize) and consists in using a droplet of mercury as an electrode, that grows, falls and is renewed. The main advantages of using a mercury drop electrode are that i) its surface and the diffusion layer are constantly renewed, and not modified by deposited material during electrochemical processes and ii) the proton reduction on mercury occurs at very high cathodic overpotentials. Thus, it is possible to observe reactions occurring at large potential values. Nowadays, European regulations (RoHS: Restriction of Hazardous Substances) limits the use of mercury, famous for being a highly dangerous metal, consequently, the pulse techniques are used with non-polarographic solid electrodes…

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