INSTALLATION
Initial
System Inspection And Setup (continued)
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Chapter:
i
Topic:
I,
Refrigeration-grade copper tubing may
be
used for all of the
gas
supply lines to the
chromatograph. Plastic tubing should never
be
usedas
it
permits contaminants, includung
oxygen,
to
permeate and this cancause damage
to
thermal
conductivity detectors (TCDs) and
capillary columns,
in
addition
to
degrading the performance of the electron capture detector
(ECD) system. Except in the case of the ECD detector, copper tubing destined for gas supply
lines may
be
rinsed out with methylene chloride, followed by methanol. If the tubing is destined
foruse
with
the
ECD,
do
not use methylene chloride or anyother halogenated solvent as this
would
wreak
havoc upon the detector indefinitely. It
is preferrable
to switch to
1/16"
slainIess
steel tubing, if available, for the ECD
gas
lines. It is also a good idea to flame the tubing with a
torch while
running
clean carrier
gas
through
it
so
that
anypossible pre-existing contaminants
will
be
eliminated from the tubing run. The tubing
is
heated until it changes color.
In
order
to
eliminate moisture from the gas supply lines,
it
is recommended
that
molecular
sieve filters
be
installed in
all
of the gas supply lines. SRI 86IOC gas chromatographs are
factory-equipped with electrically heated 1/8" x 3" molecular sieve-filters on the carrier and
sparge gas lines. Although not indispensable, an oxygen filter is a worthwhile optional addition to
an ECD carrier
gas
supply line. Extremely pure gas should
be
used exclusively on the ECD
detector (99.9995% purity).
When routing the gas lines, care should
be
taken
to
avoid creating
spots
where moisture
can
gravitate
andaccumulate.
Also,
gas lines should not
be
routed near electrical outlets due
to
the potential for short circuiting created
if
the
bare
tubing were
to
come into contact with exposed
electrical contacts, instantlymelting the tubing at the short circuit siteand releasing
gas
into the
area.
If
the gas were flammable, a torch-like flame might
be
produced.
If
the
gas
did not ignite
immediately, an explosion hazard would
be
created.
Once the gas lineconnections have beenmade and leak-tested, and the gaschromatograph
has been located in the counter-top position where it
will
be
used, plug the GC into a properly
grounded
AC outlet, and energize the unit,
Gas
pressures may then
be
adjusted to proper
operating conditions bymeans of the
gas
pressure setpoint
trimpots
located under the
red
protective ovencover. Please review the section regarding the setting of these
setpoints
for
specific information regarding their use. Connect the 6' DB-9 serial cable to the RS-232
connector on the left side control panel of the GC, and connect the opposite endof the cable
to
the COM port to
be
used for communications on the PC. At this point, start the PeakSirnple
program and
wait
for the main chromatogram screen toappear.
Once the PeakSimple program
is
running, select the F1LE- CONTROLS - CHANNELS
menu (CONTROLS - CHANNELS - DETAll.S menu in the MS-DOS version) and observe what
temperature the default temperature is programmed to. This temperature should
also
be
displayed
on the chromatograph's LED display when
digital
display has been toggled on to OVEN
ACfUAL position.
If
these two figures donotmatch within
two
degrees after a few minutes,
select the CHANNELS - TEMPERATURE menu again and verify that
if
there is a temperature
program loaded into memory, that itmeet your requirements. Otherwise youmay
edit,
replaceor
clear the displayed temperature program. Return
to
the main screen.
If
the temperatures match,
thenthedata system is communicating with the chromatograph.
If there is no
response
from the chromatograph
data
system
to
the PC, the
pert
address
(and/or
data
acquisition
type
in
the MS-DOS version)
information
may
be
set incorrectly
in
the
OVERALL screen (DETAll.S screen in MS-DOS) for each channel. This
will
typically produce
the "Channel 1not functioning" message. Verify that the proper
hardware
settings havebeen
implemented. Once this
has
been done, communication between the chromatograph and the data
system is typically established by activating the channel
in
the CHANNELS screen. Now the
systemmay be adjusted tooperating conditions.
