Title ~ Electrochemistry
Author ~ R. P. W. Scott
Section ~ Stripping Chronpotentiometry.
Stripping Chronpotentiometry (SCP)
Stripping chronpotentiometry closely resembles anode stripping voltammetry in that the analyte(s) is concentrated onto a mercury electrode surface. The metal amalgam is then oxidized (stripped) chemically from the working electrode surface.
Examples of the oxidation agents that might be used is (O2), Hg(II) and Cr(VI). Alternatively the amalgam can be removed by passing a constant anodic current through system. Whichever technique is used, the potential of the working electrode is monitored over the oxidation period and the potential of the working electrode is recorded with respect to time in the manner that is diagrammatically shown in figure 21. A sudden change in working electrode potential will take place when all the respective metal has been stripped from the electrode.
Figure 21. A Potentiogram
of the Stripping Chronopotentiometric Analysis of a
Sample Containing Zinc (II), Cadmium (II), Lead (II) and Copper (II)
The time needed for the oxidation of a
given metal (the step length as shown in figure 21), (tM)
will be proportional to the amount of the respective metal in the cell.
