Diagnosable remotely - YES
Fixable remotely - YES
**Problem is only relevant to Z-NTA instruments**
This used to be a very common issue on older ZetaView's but is less common and easier to fix on newer models. It ususally occurs at the start of the Auto-Alignment function, or the start of a zeta potential measurement.
There are a few reasons why it may happen, most of which are resolvable by the customer themselves with guidance.
Air bubbles:
If a large air bubble is present inside the measuring cell, it can prevent the flow of an electrical current across the cell resulting in the low voltage error.
SOLUTION - rinse thoroughly with water (and air if needed) then reinject plenty of the PS100 suspension and repeat.
Wet electrical connections:
If the measuring cell has been removed for cleaning and not dried properly, water on the outer surface of the cell or around the metal flanges can cause issues with the electrical field.
SOLUTION - remove the cell and thoroughly dry the outside with tissue (CAUTION - be very careful not to touch the optical windows!). Also dab dry the metal flanges at each end of the cell. Reinstall the cell and re-initialise.
Poor connection between cell and cell assembly:
If the cell is not properly seated inside the cell assembly, it can interfere with the electrical field.
SOLUTION - tighten the two screws which hold the cell carrier in place.
Corroded electrodes:
The driver electrodes can become corroded over time. This is accelerated by repeated zeta potential measurements in high-salt buffers such as PBS. Depending on the degree of corrosion, the electrodes can sometimes be re-conditioned. The condition of the electrodes can be indicated by getting the customer to take pictures from within the cell assembly, with the cell carrier removed, like below.
If the corrosion is fairly light, an Analytik engineer can re-condition the electrodes by polishing them. This cannot be done by the customer as it involves advanced disassembly. The procedure for polishing electrodes is documented in the ZetaView Z-NTA PM Procedure, and a video tutorial can be found here:
If the electrodes are not removable (old PMX110 models) then the only solution is a new cell assembly. Consult with PMX. If the electrodes are removable but heavily corroded, they need to be replaced. Consult with PMX.
SOLUTION - arrange a site visit to re-condition electrodes if possible. Consult with PMX about replacement if not.