PotentiometricStrippingAnalysis

Two-step electrochemical measurement in which 1) material is accumulated at an electrode and 2) the material is removed by chemical reaction or electrochemically at constant current with measurement of electrode potential. Historically for the analysis of metal ions, mercury ions were added to the test solution to form a mercury amalgam when reduced. Alternatively, an HMDE or MFE was used and the oxidizing agent added after amalgam formation. However, the toxicity of mercury and its compounds have all but precluded the present-day use of mercury. The accumulation is similar to that used in stripping voltammetry. The stripping potentiogram shows staircase curves of potential as a function of time. Frequently, the first derivative is displayed (dE/dt=f(t)), as this produces peak-shaped signals. The time between transitions (peaks) is proportional to the concentration of analyte in the test solution. The time between changes in potential in step 2 is related to the concentration of analyte in the solution.