Square-wave Voltammetry Purpose

Square-wave Voltammetry (SWV) is used for both quantitative chemical analysis and study of the mechanism, kinetics, and thermodynamics of chemical reactions.

SWV used as an analytical tool offers three major advantages when compared to other electrochemical techniques.

• SWV is very sensitive, often allowing direct analyses at the ppb (parts per billion) level and even the low ppt (parts per trillion) level when used in a stripping mode.
• SWV requires less time per sweep than older techniques such as differential pulse polarography. A SWV sweep can often be recorded in less than ten seconds, in contrast with a differential pulse polarogram that typically requires more than two minutes for data acquisition.
• The square-wave frequency can be used to differentiate between processes with fast and slow kinetics. In some cases, kinetically fast processes can be measured without interference from slower processes that occur in the same potential range.

Other techniques, such as cyclic voltammetry, are generally preferred over SWV for mechanistic and kinetic studies. However, square-wave voltammetry’s sensitivity allows mechanistic and kinetic measurements in solutions that are too dilute for more conventional study.

SWV is generally performed on a stationary solid electrode or a hanging mercury drop electrode. The SWV script in the Pulse Voltammetry software provides for mercury-drop generation, solution de-aeration, and experiment sequencing suitable for the most common applications for square-wave voltammetry.

Choose the type of electrode in the Electrode Setup Panel.

Additional sequencing steps suitable for square-wave anodic (or cathodic) stripping are implemented in the Pulse Voltammetry’s SWS (square-wave stripping) technique.