- Anodic stripping voltammetry
Anodic stripping voltammetry is a voltammetric method for quantitative determination of specific ionic species. The
analyteof interest is electroplated on the working electrodeduring a deposition step, and oxidizedfrom the electrode during the stripping step. The current is measured during the stripping step. The oxidation of species is registered as a peak in the current signal at the potential at which the species begins to be oxidized. The stripping step can be either linear, staircase, squarewave, or pulse.
Electrochemical Cell Set-Up
Anodic stripping voltammetry usually incorporates three electrodes, a
working electrode, auxiliary electrode(sometimes called the counter electrode), and reference electrode. The solutionbeing analyzed usually has an electrolyteadded to it. For most standard tests, the working electrode is a mercury film electrode. The mercury film forms an amalgamwith the analyte of interest, which upon oxidation results in a sharp peak, improving resolution between analytes. The mercury film is formed over a glassy carbonelectrode. A mercury drop electrode has also been used for much the same reasons. In cases were the analyte of interest has an oxidizing potential above that of mercury, or where a mercury electrode would be otherwise unsuitable, a solid, inert metal such as silver, gold, or platinummay also be used.
Anodic stripping voltammetry usually incorporates 4 steps if the working electrode is a mercury film or mercury drop electrode and the solution incorporates stirring. The solution is stirred during the first two steps at a repeatable rate. The first step is a cleaning step; in the cleaning step, the potential is held at a more oxidizing potential than the analyte of interest for a period of time in order to fully remove it from the electrode. In the second step, the potential is held at a lower potential, low enough to reduce the analyte and deposit it on the electrode. After the second step, the stirring is stopped, and the electrode is kept at the lower potential. The purpose of this third step is to allow the deposited material to distribute more evenly in the mercury. If a solid inert electrode is used, this step is unnecessary. The last step involves raising the working electrode to a higher potential (anodic), and stripping (oxidizing), the analyte. As the analyte is oxidized, it gives off electrons which are measured as a current.
Anodic stripping voltammetry can detect μg/l concentrations of analyte.
Cathodic stripping voltammetry
Adsorptive stripping voltammetry
# Wang, J. (1985). Stripping Analysis: Principles, Instrumentation, and Applications, VCH Publishers, Inc., Deerfield Beach, Florida.
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