To Isolate The Cause Of Fid Noise - Agilent Technologies 7890 Series Troubleshooting Manual

To Isolate the Cause of FID Noise

Agilent 7890 Series Troubleshooting
FID noise is the result of mechanical, electrical and chemical
factors. FID noise can be a subjective parameter. Often FID
baseline noise is perceived based on history of a given detector
or comparison with another detector in the lab. For proper
diagnosis of noise it is important to evaluate the detector noise
under documented conditions against a known standard. Find
more detailed information about noise in
Including Wander, Drift, and Baseline
Before troubleshooting the detector, perform a noise test using
your Agilent data system. If the detector fails the noise test,
then troubleshoot the cause as described below.

To isolate the cause of FID noise:

1
If the noise test fails, remove the column and re-evaluate
detector noise with the FID capped and re-ignited, using only
H2/air and makeup detector gases. If it passes, suspect
contaminated column/carrier gas.
2
If the noise failed with no column installed, repeat the noise
test with only H2 and air - set makeup flow to "Off". If it
passes, suspect contaminated makeup gas.
3
If the noise test still fails, see
Current. If the leakage test fails, replace or clean the
collector and PTFE insulators, the interconnect with spring,
and/or the entire FID electrometer assembly. If the leakage
test fails, replace or clean the
the interconnect with spring, and/or the entire FID
electrometer assembly.
4
If the leakage current test is OK, suspect a contaminated jet
or contaminated H2 or Air detector gas supplies (gases,
tubing, traps), especially if the background of the detector
when lit is >20 pA.
Troubleshooting Tasks
Noisy Detector,
Spikes.
To Measure FID Leakage
collector and PTFE insulators,
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