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Potentiometry passively measures the potential of a solution between two electrodes, affecting the solution very little in the process. One electrode is called the reference electrode and has a constant potential, while the other one is an indicator electrode whose potential changes with the sample's composition. Therefore, the difference in ...
Reference electrodes generally used are hydrogen electrodes, calomel electrodes, and silver chloride electrodes. The indicator electrode forms an electrochemical half-cell with the interested ions in the test solution. The reference electrode forms the other half-cell. The overall electric potential is calculated as
An ion-selective electrode (ISE), also known as a specific ion electrode (SIE), is a simple membrane-based potentiometric device which measures the activity of ions in solution. [1] It is a transducer (or sensor ) that converts the change in the concentration of a specific ion dissolved in a solution into an electrical potential .
Cathodic stripping voltammetry is a voltammetric method for quantitative determination of specific ionic species. [6] It is similar to the trace analysis method anodic stripping voltammetry, except that for the plating step, the potential is held at an oxidizing potential, and the oxidized species are stripped from the electrode by sweeping the potential negatively.
Whether the analyte is reduced or oxidized depends on the analyte and the potential applied, but its reaction always occurs at the working/indicator electrode. Therefore, the working electrode potential varies as a function of the analyte concentration. A second auxiliary electrode completes the electric circuit, called the counter electrode.
The resulting current can be mathematically predicted and modeled. Among the most common hydrodynamic setup involves the working electrodes rotating to create a laminar flow of solution across the electrode surface. Both rotating disk electrodes (RDE) and rotating ring-disk electrodes (RRDE) are examples where the working electrode rotates ...
The connection can be direct, through a narrow tube to reduce mixing, or through a salt bridge, depending on the other electrode and solution. This creates an ionically conductive path to the working electrode of interest. A reference electrode is an electrode that has a stable and well-known electrode potential.
The counter electrode, also known as the auxiliary or second electrode, can be any material that conducts current easily, will not react with the bulk solution, and has a surface area much larger than the working electrode. Common choices are platinum and graphite. Reactions occurring at the counter electrode surface are unimportant as long as ...