How to Work with the Test Cell FlexCell

The choice of the sealings is depending on the kind of sample and electrolyte.
For measurements of gas diffusion electrodes, use flat silicone sealings.
For measurements in very strong alkalis and acids at high temperatures, we offer sealings made of PTFE.
For poorly conductive electrodes, we offer sealings made of graphite.
O-rings are recommended for metal sheets. Suitable for alkaline solutions are O-rings made of EPDM.
For use in acids, we recommend O-rings made of FKM.

The cell can be filled with approx. 30 ml of electrolyte through the opening in the cover. Pour in the last ml slowly and observe the filling level in the hole for the reference electrode, which may rise with a delay. The hole should be no more than half full to avoid overflow when setting the reference electrode. If the hole does not fill with electrolyte, an air bubble in the Haber-Luggin capillary is blocking the electrolyte flow. Tilt the measuring cell slightly to allow the air bubbles to escape. 

Avoid an electrolyte film between reference electrode and working electrode because a film can lead to a short circuit.

Due to the limited electrolyte volume of approximately 30 ml, the test duration is limited to 24h or several days, depending on the current density and the temperature (water evaporation losses).

Yes, you can purge the cell with Argon, for example. Make sure that the purge rate is low to avoid removing too much water vapour.

It is usually sufficient to rinse the cell thoroughly with water after disassembly. Deposits can be removed mechanically using a suitable laboratory brush. Stubborn metal deposits such as silver or copper can be removed with nitric acid.

You can remove the counter electrode for cleaning or replacing it. Take a look at our video.

The screw connections may not be sealed. Please tighten them. Also, check that the O-ring or silicone sealing is properly seated. You can also check the contact screws and the fixing pins for this.

This could be due to poor contact. Please check the connection cables of the heating elements. Alternatively, the silicone-coated PTC heating element may be defective. Check the resistance of the heating elements when cold:
FlexCell PTFE: 5 Ohm
FlexCell PP: 3 Ohm

There may be gas bubbles in front of the reference electrode. Move the reference electrode up and down a few centimeters. The gas bubbles may also be blocking the Haber-Luggin capillary. In this case, remove the air from the reference electrode hole using a pipette ball.
Contaminations, degradation products, corrosion products can lead to incorrect measurements, too.
Please check the measuring cables if there are any visual damages such as corrosion, cracks or sessile plugs. Replace the cables.
An infirm battery of handheld multimeter can lead to wrong voltages, too.

The potentiostat often reacts very delicate to electrolytes and/or samples with inadequate conductivity or gas bubbles in the Haber-Luggin capillary. It begins to oscillate.
The impedance of the reference electrode or Haber-Luggin capillary may be too high. Please adjust the current range of the potentiostat.
If using an analyte compartment, please insert the reference electrode into it. You can find more helpful information here: What-can-cause-my-experiment-to-be-noisy.

This could be due to poor contacts. Check the connecting leads of the potentiostat, and the multilam plugs of the cell.

Alternatively, the Pt counter electrode could be the problem. Remove the counter electrode and check its condition.