Cell current shows large continuous drift

Applies to

Electrochemical detection

Summary

A large drift in baseline is noticed.

Cause

Malfunctioning reference electrode, for example because of air in the REF compartment of the salt bridge or poor connection in the cell cable. Also a sudden contamination could cause this.

Remedy

1. Perform a dummy cell test, if not passed it is most likely an electronic malfunction (or cell cable, see below)
2. Perform a stop flow test to rule out contamination of some sort
3. In case an Analogue Data Output is used with an AD convertor (i.e. not using the digital data via Clarity): connect both wires from the detector with a + (signal) and – (shielding) of the AD-convertor. In some cases the AD convertor has an additional ground pin. But this might be a “floating” ground resulting in drift.

 Related to reference electrode, or cell cable:

1. Maintenance of reference electrode (salt bridge), double check for bubbles, remove air/bubbles if those are visible
2. In case of ISAAC/HyREF check the electrode looks clean. ISAAC is dark brown/grey. The HyREF should have a metal shine. Polish the inlet block with the REF and apply maintenance as in the manual if needed.
3. Install the REF properly, without including air in the block cavity (salt bridge) or cell.
4. Look for sign of corrosion on connectors, replace cell cable.
5. Incorrect detector settings, method not optimized.