eDAQ Picostat, Руководство пользователя

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Appendix B — Troubleshooting 97
The results show peaks or steps at the inverse polarity I expect to see
(i.e. a peak may be occurring at 0.5 V when it should be at –0.5 V).
• Check that you are connected to the correct Output (+ or –) of the
e-corder . See Connecting the Potentiostat, page 11 , or Connecting
the Picostat, page 31 , or Connecting the QuadStat, page 48 .
• If you are using Chart or Scope, software check that the Invert box
is checked or not, as appropriate, for the potential recording
channel.
The results show peaks (or steps) at different potentials than you expect.
• See previous section.
• Make sure the reference electrode is connected to the correct
(yellow) lead wire,
page 7 , page 27or page 43 . Connection of the
reference electrode to either the working or auxiliary leads can also
cause rapid electrode deterioration requiring electrode replacement.
• Check the condition of the reference electrode. All reference
electrodes age. For example and Ag/AgCl electrode will age with
exposure to light. Eventually the white/light grey coating of AgCl on
the central silver wire will be replaced by a brown/black coating of
silver oxide. As this process takes place the apparent positions of
your voltammetric peaks will appear to shift to different potentials.
Most Ag/AgCl electrodes can be quickly regenerated by placing
the silver wire in 1 M hydrochloric acid solution for a minute or two
(any silver oxide is quickly reconverted to AgCl), although you may
wish to remove the old coating completely and re–chloridize the
silver wire to ensure a good coating of fresh AgCl. In either case
replace the newly coated wire back into the electrode casing with
freshly prepared KCl solution. Aged calomel (Hg/Hg
2
Cl
2
)electrodes
should usually be replaced. Reference electrodes using a gelled
electrolyte will deteriorate if the gel dries out.
The results show peaks in the negative current direction when you want
them in positive direction.
• Check that the Invert box is checked or not, as appropriate, for
the current recording channel. See Inverting the Signal on
page 18 ,
page 37, or page 56.