Agilent Technologies 8860 User Manual page 48

6 Maintenance and Troubleshooting
Chromatographic symptoms
Contamination or carryover
If your output has contamination or unexpected peaks, do the following:
Isolate the source
1 Disconnect the sample cylinder, connect with a N
If the contamination disappears, the problem may be either in the sample or in the connecting
tubing (or in the quick connector or filter that installed between gasifier and sample cylinder).
2 Perform a blank run. 
If the contamination disappears, the problem is in the gasifier.
3 If it's caused by GC system, refer to the Troubleshooting section of the GC User Manual for
information about how to eliminate the carryover.
Eliminate contamination or carryover caused by gasifier/sample supply
• Check for sample carryover from previous runs, purging the system using N
ghost peaks/carryover go away or get smaller. Make sure the vent outlet is not end capped.
Using gas like N
sample analysis.
If necessary, do the following:
• Increase the gasifier vent flow to assist the purging process.
• Increase the gasifier vaporizer temperature to 150 °C to help baking out the contaminates
• Check for supply tubing and fitting contamination. Try new or clean filter/quick connector to
see if ghost peaks/carryover disappear.
• Try to backflush the system:
1 Disconnect the sample cylinder from the sample inlet, connect a tubing to exhaust vent if
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to throughly purge the whole gasifier system prior to subsequent
2
needed.
source. Perform a N
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Agilent 8860, 8890, and 990 Micro GC Gasifier User Manual
blank run. 
2
to see if the
2