Agilent Technologies 5975T LTM GC/MSD, Troubleshooting And Maintenance Manual

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20 Troubleshooting and Maintenance Guide
1
Introduction
Dangers unique to GC/MSD operation
Hydrogen presents a number of dangers. Some are general,
others are unique to GC or GC/MSD operation. Dangers include,
but are not limited to:
• Combustion of leaking hydrogen.
• Combustion due to rapid expansion of hydrogen from a
high-pressure cylinder.
• Accumulation of hydrogen in the guard column heated zone
and subsequent combustion.
• Accumulation of hydrogen in the MSD and subsequent
combustion.
Hydrogen accumulation in a GC/MSD
All users should be aware of the mechanisms by which
hydrogen can accumulate (
Table 3 ) and know what precautions
to take if they know or suspect that hydrogen has accumulated.
Note that these mechanisms apply to
all mass spectrometers,
including the GC/MSD.
WA R N I N G
The instrument cannot detect leaks in inlet and/or detector gas
streams. For this reason, it is vital that column fittings should
always be either connected to a column or have a cap or plug
installed.
Table 3 Hydrogen accumulation mechanisms
Mechanism Results
Mass spectrometer turned off A mass spectrometer can be shut down
deliberately. It can also be shut down
accidentally by an internal or external failure.
A mass spectrometer shutdown does not shut
off the flow of carrier gas. As a result,
hydrogen may slowly accumulate in the mass
spectrometer.