Bridge Tube And Reference Electrode; Counter Electrode; Gas-Flow Overview And Terminology - Gamry Instruments MultiPort Operator's Manual

Assembly--Bridge Tube and Reference Electrode

Bridge Tube and Reference Electrode

The Bridge tube fits any of the #7 ports on the top, but it is designed for the #7-to-15/28 adapter included. It
can be adjusted in depth and position. Generally position it with the tip near the sample but not touching.
Always use the included ball-joint clamp, for the joint is not stable without it.
The bridge tube allows the reference electrode to be placed outside the test solution, isolating it from thermal-
gradient experiments and more caustic test solutions. Ensure that the bridge tube is filled to the tip with a
conductive solution (the test solution when possible) for ideal performance of the reference electrode.
Insert the reference electrode into the #11 thread at the upper end of the bridge tube. The reference electrode
must contact the test solution inside the tube. Various reference electrodes that work with this system are
available; contact us for details.
Figure 3
Reference Bridge Tube

Counter Electrode

The Counter Electrode is a rod of very-high-density graphite.
To fit the counter electrode to the cell, first roll on one of the small black washers. With the washer on, feed the
counter through any of the available #7 ports on the top and secure with a bushing. Leave at least half an inch
exposed for electrical contact.
The graphite rod that is shipped with your MultiPort Cell Kit is spectroscopic grade. It is very pure and is
therefore unlikely to be a significant source of contamination in your initial experiment. However, the rod is
somewhat porous and can adsorb substances present in your test solution. If you reuse a graphite rod, it can
contaminate your test solution. The effect is small, and you are unlikely to see it unless the test solution changes
drastically between tests. If this is a concern to you, consider a platinum counter electrode, possibly with a
fritted glass tube (available from us) to isolate it further from the test solution.

Gas-flow Overview and Terminology

The Gas Dispersion Tube may or may not be required for your experiment. Most of the cases in which you use
it involve the removal of atmospheric oxygen from the test solution.
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