Preventive Maintenance
Electron capture detector (ECD)
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Electron capture detector (ECD)
Frequency test
Note: For high sensitivity operation, and starting from a cold system, 24
hours may be necessary before baseline is completely stabilized. Use
low•bleedsepta and condition a new septum prior to use in an unused
inlet for several hours with 1 to 5 ml/min carrier flow rate.
Using normal operating conditions, and allowing at least two hours after
the last sample was injected, enter the following:
DET A
( or
B
)
ON
SIG 1
( or
SIG 2
)(
A
or
B
)
If the displayed value exceeds 100 (1000 Hz), indicating a high
background signal, investigate the following possibilities:
Contaminated carrier gas trap(s) and/or supply
Insufficient column conditioning
Contaminated detector
Column, inlet, and/or septum bleed
Leaks
Anode insulation leakage
Carrier gas evaluation
Because of its very high sensitivity, the ECD is particularly prone to
contamination problems, including contaminants entering the system via
the carrier gas source.
The following procedure should be performed whenever a new carrier gas
source is installed:
1. With the instrument on and operating normally, cool the oven to
ambient, turn off the detector, turn off carrier flow to the detector, and
