Operating in Electron Ionization (EI) Mode 3
5977 Series MSD Operation Manual 53
The EI GC/MSD Interface
The GC/MSD interface (Figure 11 on page 54) is a heated conduit into the MSD
for the capillary column. It is bolted onto the right side of the analyzer
chamber, with an O-ring seal. It has a protective cover which should be left in
place.
One end of the GC/MSD interface passes through the side of the gas
chromatograph and extends into the GC oven. This end is threaded to allow
connection of the column with a nut and ferrule. The other end of the
interface fits into the ion source. The last 1 to 2 mm of the capillary column
extend past the end of the guide tube and into the ionization chamber.
The GC/MSD interface is heated by an electric cartridge heater. Normally, the
heater is powered and controlled by Thermal Aux #2 heated zone of the GC.
The interface temperature can be set from MassHunter Data Acquisition or
from the gas chromatograph. A sensor (thermocouple) in the interface
monitors the temperature.
The GC/MSD interface should be operated in the 250 to 350 C range. Subject
to that restriction, the interface temperature should be slightly higher than the
maximum GC oven temperature, but never higher than the maximum column
temperature.
The EI GC/MSD interface can only be used with an EI ion source. There are
two types of tip seals that may be used with EI ion sources. The standard/inert
EI ion sources do not need a tip seal. The extractor ion source on an EI only
system uses a tip seal (G3870-20542). The extractor ion source and the CI ion
source on an EI/CI system uses the CI tip seal (G1999-60412).
See also
“To Install a Capillary Column in the GC/MS Interface” on page 38.
WARNING
The GC/MSD interface operates at high temperatures. If you touch it when it is hot,
it will burn you.
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