Metrohm 2.946.0010, Manual

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7 Troubleshooting
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65
Figure 19 Influence of pH on the background current of the scTRACE
Gold electrode.
~
pH 2
(c(KCl) = 50 mmol/L, c(H
2
SO
4
) = 10 mmol/L)
~
pH 5 (c(KCl) = 50 mmol/L)
~
pH 12
(c(KCl) = 50 mmol/L, c(NaOH) = 10 mmol/L)
For a determination that means that only substances which show a peak
more positive than -0.5 V can be determined in an acid electrolyte. At
more negative potentials the current deriving from the H
+
reduction will
overlay any other analytical signal. If a neutral or alkaline electrolyte can
be used for the application, also substances showing a peak between -0.5
V and -1.5 V can be determined.