BAS 100B/W - Page 36

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
.