Agilent Technologies 5975C TAD VL MSD, Troubleshooting And Maintenance Manual

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Introduction
1
5975 Series MSD Troubleshooting and Maintenance Manual 21
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 GC oven and subsequent combustion (see
your GC documentation and the label on the top edge of the GC oven door).
•
Accumulation of hydrogen in the MSD and subsequent combustion.
Hydrogen accumulation in an MSD
All users should be aware of the mechanisms by which hydrogen can
accumulate (
Table 4 ) 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 MSD.
WA R N I N G
The MSD 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 4 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.