Diagnostics; Frequency Test - Agilent Technologies 6890 Series Service Manual

341 Micro-cell Electron Capture Detector (µ-ECD)

Diagnostics

Diagnostics

Frequency test

Perform this test to make sure that the base frequency for the µ-ECD during
a blank run indicates a relatively contaminant-free system.
It may take 24 hours for the µ-ECD baseline to completely stabilize, especially
Note
if you are starting with a cold system and want to assure high-sensitivity
operation.
Therefore, for the most accurate results, run the detector at normal operating
conditions for as long as possible (at least 2 hours and up to 24 hours) before
running the frequency test.
If you will be injecting into an unused inlet, you must use low-bleed septa.
Make sure to condition new septa before use in an inlet for several hours with
1 to 5 mL/min carrier flow.
1. Make sure you are using normal operating conditions and that at least
2 hours have elapsed since the last run.
Turn on the µ-ECD and the corresponding signal.
2.
3. Check the displayed "Output":
•
•
Note Each display count equals a frequency of 1 Hertz (e.g., a display reading of
100 = 100 Hz.).
If the µ-ECD frequency indicates contamination (≥1000) check for the
4.
following:
•
22 of 26
<25 = µ-ECD frequency is acceptable
≥1000 = Contaminants in system
Contaminated carrier gas trap(s) and or supply—replace carrier gas
supply tank and any traps on the carrier supply line.
Detectors
Agilent 6890 Gas Chromatograph Service Manual
Jun 2001