Deposition potential
A further parameter which can influence the peak area (analytical signal) is the deposition potential.
Figure 4 demonstrates the change in the analytical signal with deposition potential.
For lead and copper, a stable signal for each metal was observed at a depostion potential around –700 mV (vs. SCE). At this potential no cadmium peak was observed.
The cadmium peak appears at a potential more negative than –900 mV (vs. SCE).
For all determined elements, a maximum in the peak area was observed at a deposition potential of –1200 mV.
At more negative potentials, a decrease in the analytical signal was observed, probably due to hydrogen volution and subsequent destruction of the mercury film.