4-6
Figure 4-8. Controlled Growth dialog box.
The CGME can also be used as a DME when in the CGME mode by activating the
Controlled DME check box. This will open the valve at the start of the experiment
and close it at the end of the experiment. The mercury will flow freely during the
course of the experiment and the Dropping Time (i.e., the time between activations
of the drop knocker) is selected using Specific Parameters (the natural drop time at
low potentials in aqueous solution for the standard 150
µ
m capillary is typically
slightly less than 1 s).
The CGME mode can also be used for anodic stripping voltammetry (Z. Kowalski
and J. Migdalski, Electroanalysis 4 (1992) 915). The mercury drop is grown
incrementally during the deposition step using a series of pulses. The drop size is
again determined by the Pulse Width and the Number of Pulses, which are entered
under Drop Control for Deposition. The incremental growth in activated by clicking
the Drop Control for Deposition check box. The Delay Time is determined by the
Deposit Time and the Number of Pulses: if the Deposit Time is 60 s and the
Number of Pulses is 4, then the pulses will occur at the beginning and at 15, 30 and
45 s of the Deposit Time.
