32 Troubleshooting and Maintenance Manual
2 General Troubleshooting
Baseline wanders
• Insufficient carrier gas supply pressure*
• Malfunctioning flow or pressure regulator*
• Intermittent leak in the GC inlet*
* This could cause a fault condition in the GC that would prevent the GC
from operating.
Retention times for all peaks drift – shorter
• Column has been shortened
• Initial oven temperature was increased
• Column is getting old
Retention times for all peaks drift – longer
• Column flow has been reduced
• Initial oven temperature was decreased
• Active sites in the sample path
• Leaks in the GC inlet*
* This could cause a fault condition in the GC that would prevent the GC
from operating.
Poor sensitivity
• Incorrect tuning, or tune file that does not match the type of analysis
• Repeller voltage is too low
• Incorrect temperatures (oven, GC/MS interface, ion source, or mass filter)
• Incorrect sample concentration
• Leaking GC inlet*
• Dirty GC inlet
• Incorrect split ratio
• Purge-off time in splitless mode is too short
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