Dummy cell test failed
Electrochemical detector, dummy cell test
Dummy cell test is failed. Noise or I-cell out of spec.
- Noise too high: problem in electronics, data acquisition or connecting cables.
- Too much drift: electronic or heater problem, too short equilibration time
- Current (Icell) too low or high: problem in electronics, if original cell cable is used: look for corrosion.
A few checks can be done, before contacting Antec.
- Noise: is sometimes caused by a cell cable that is dangling in front of the air flow of a fan. Put it aside, use a piece of tape if needed. Also clear the cell compartment from any other wires or metal tubings that go in. They may work as an antenna and pick up noise. Close the cell cabinet door correctly to ensure a functional noise free Faraday cage.
- Drift: a drift issue is usually due to short stabilization times. Repeat after 30 min with door closed to have the system stabilize, do not open the door just start again.
- Icell too high/low: in case of small discrepancies (i.e. 2.5 or 2.8 instead of 2.67 nA) it is most likely a zero IE or Ecell calibration parameter. Such calibration can be done in the service mode by an Antec trained engineer. In case of much larger differences (i.e. current is 40 nA or 0 nA, no current) there is most likely something wrong in the electronics.
Using the dummy cell test in Antec’s Dialogue software will automatically repeat a dummy cell test when noise or drift is a bit out of spec. With the “noise monitor” on, the test restarts every 6 min until in spec. It continues to finalize the test automatically. In case no dummy cell is available, or a cable/dummy cell issue is suspected, the detector has an internal dummy cell as well. In Dialogue software this internal dummy can be switched on after the automated dummy cell test has been started. Do not connect a flow cell if Icell in the display shows a value far beyond the value expected by using the dummy cell e.g. >> 10 nA if 2.6 nA is expected. Damage may occur to the flow cell which is not covered by warranty.
Description of dummy cell test in ECD user manuals, see manuals. KB paper about internal/external dummy cell test and about the dummy cell test.