Agilent Technologies 6850 Series II User Information page 201

Routine Maintenance: Detectors
Maintaining a Microcell Electron Capture Detector (µECD)
Correcting performance problems
Performance problems, such as an output reading that is too high or too low or
unsatisfactory chromatographic results (for example, a noisy baseline), can be
caused by leaks or deposits in the detector or other part of the
chromatographic system. To determine the location of the problem, you need
to perform a series of tests.
Before testing the detector, consider the nature of the problem. If you have
recently made a change to the GC system and now see an elevated output level,
there is a good chance that the change has either introduced contaminants or
caused a leak in the system. For example, if you recently switched gas supplies,
the new gas may contain impurities. Or if you recently installed a new column,
there could be a leak at the detector fitting.
If the output value or noise level has been increasing gradually, the cause is
probably a slow build-up of deposits. The detector may contain contaminants
from column bleed or a trap may be saturated. If the change has been gradual
and if you have not modified the GC system recently, you can probably start by
checking for contamination. Note: Contamination in this procedure refers to non-
radioactive deposits from such things as column bleed or dirty samples!
Released: March 2004 6850 Series II GC User Information page 201 of 256