The Importance of Haber-Luggin Capillaries
The underestimated connection of a reference with electrolyte in electrochemical test cells.
Haber-Luggin Capillary - the underestimated connection
The electrolytical contact between the working and the reference electrode is made by the Haber-Luggin capillary. It has to be positioned directly in front of the working electrode to minimize the voltage drop (IR-drop) across the electrolyte. The Haber-Luggin capillary must have a small diameter to avoid interrupting the field line course. The diameter, in turn, must be so big that the IR-drop is low. It has to be impervious to gas bubbles which block the capillary.
The Haber-Luggin capillary should have a diameter of 1 mm and positioned at a distance of 0.5 to 1 mm to the working electrode. A closer distance will form shielding effects.
In our test cells FlexCell and ElyFlow, the Haber-Luggin capillary is filled with a solid electrolyte. In this way, we avoid an accumulation of gas bubbles in the capillary, which could lead to a dramatic increase in resistance. Thereby, potentiostats can begin oscillating, ruining the measurements. From a quality assurance perspective, it is also important that all of these factors remain stable across different half cells. CNC-technology in plastic allows the precise positioning of the Haber-Luggin capillary to the working electrode. This ensures the comparability of measurements among each other and between test cells.
Would you like to learn more about this topic?
The Importance of Field Lines
Homogeneous electric field lines are required for correct measurements. Here you can learn more about parallel field lines, equipotential surfaces and IR-drop.
FlexCell - Electrochemical Test Cells
FlexCell is the optimized voltammetry test cell for electrochemistry with a three-electrode set-up. Here you can find some general information and take a look at the cross section of FlexCell.
ElyFlow - Electrochemical Test Cell
ElyFlow is a test cell optimized for electrolyte circuits for electrochemistry with a three-electrode set-up. Here you can find some general information.