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Dionex ED50A Electrochemical Detector
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2.4
Amperometry Cell
NOTE For more details, refer to User's Compendium for
The Dionex ED50A amperometry cell is a three-electrode voltammetric cell. It is
a miniature flow-through cell with a titanium cell body (the counterelectrode) (see
Figure 2-4), a working electrode, and a combination pH–Ag/AgCl reference
electrode. The type of working electrode used depends on the application. Four
standard (non-disposable) working electrode types are available: gold, platinum,
silver, and glassy carbon. Disposable working electrodes are available for certain
applications.
Oxidation or reduction of analyte molecules is accomplished by applying a
potential between the working electrode and the reference electrode. The applied
potential can be held constant or pulsed. The current is measured between the
working electrode and the counterelectrode, either continuously or at
predetermined intervals.
Changes in the potential applied between the working electrode and the reference
electrode are developed between the working electrode (where analyte reduction
or oxidation takes place) and the solution. To maintain a constant potential
difference between the reference electrode and the solution, the cell current must
be prevented from flowing through the reference electrode. A section of the
Dionex ED50A electronic circuit (the potentiostat) diverts the cell current through
the counterelectrode. The potentiostat automatically compensates for the solution
resistance between the reference electrode and the counterelectrode.
2-10
A green LED indicates normal operation.
A red or yellow LED indicates a fault. If a fault occurs, the Dionex
ED50A enters its diagnostic state and no other control is permitted
until the fault is corrected. Turn off the power to the Dionex ED50A
for a few seconds and then turn it on again. If the power fault remains,
contact Technical Support for Dionex products.
Electrochemical Detection (Document No. 065340). The
manual is the primary source of product information, as
well as basic troubleshooting help, for electrochemical
cells and electrodes.
Doc. 065551-01 6/13
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