Peaks Not Displayed/No Peaks - Agilent Technologies 7697A Troubleshooting Manual

Peaks Not Displayed/No Peaks

Agilent 7697A Troubleshooting
This topic assumes that peaks are no longer displayed when
analyzing a sample using an existing method (not during
method development).
• Check the GC.
• Check for error messages and log entries.
• If possible, mount an automatic liquid sampler (ALS)
over the inlet and inject a sequence of internal or
calibration standard directly into the inlet. If peaks
appear then the problem is not in the GC.
• If the problem is in the GC, refer to the GC's
documentation for troubleshooting procedures.
• Check the HS sequence log, event log, and status displays
for messages. Especially check the sequence log for
method deviations and dynamic leak check failures.
• Check the vial pressurization gas pressure setting. The
vial pressurization setpoint should not be less than the
pressure developed in the vial during equilibration. (If
not, you will vent sample.)
• Check the delivery gas pressures to the HS. See the
Preparation Guide. The gas delivery pressure at the HS
vial gas bulkhead fitting should be 138 kPa (20 psi)
greater than the highest desired vial pressurization
setpoint.
• Enable dynamic leak checking. This feature verifies that
each sample vial is leak- free.
• If not enabled, check the sample vial for cracks or
other leaks. See the
• If using dynamic leak checking, make sure the entered
leak rate is appropriate for the sample and its
preparation technique.
• Confirm the six port valve is turning.
• Check for leaks in the HS.
• Check for leaks in the transfer line to the GC inlet,
including the connection to the inlet.
• Check for a broken transfer line. Verify there is a flow
of carrier gas from the HS to the GC inlet.
• Check for leaks in the other parts of the sampling
system (probe, six port valve, and lines and fittings
between).
Chromatographic Symptoms
Operation Guide.
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