HP 5973, Hardware Manual

Page: 70 / 297

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3 Troubleshooting the MSD
Chromatographic symptoms
Chromatographic symptoms
This section describes symptoms you may observe in the chromatograms gener-
ated by data acquisition. In general, these symptoms do not prevent you from
operating your GC/MSD system. They indicate, however, that the data you are
acquiring may not be the best data obtainable. These symptoms can be caused by
instrument malfunctions but are more likely caused by incorrect chromatographic
technique.
Two of the symptoms: If sensitivity is low and If repeatability is poor , also apply
to mass spectral data.
No peaks
If an analysis shows no chromatographic peaks, only a flat baseline or minor noise,
run one of the automated tune programs. If the MSD passes tune, the problem is
most likely related to the GC. If the MSD does not pass tune, the problem is most
likely in the MSD.
Passes tune
• Incorrect sample concentration
• No analytes present
• Syringe missing from the ALS or not installed correctly
• Injection accidentally made in split mode instead of splitless mode
• Empty or almost empty sample vial
• Dirty injection port
• Leaking injection port*
• Loose column nut at the injection port*
* These could cause a fault condition in the GC that would prevent the GC from
operating.