Chapter:
Topic:
INSTALLATION
Dual Oven 86IOC
Gas
Chromatograph Chassis
Dual,
iDdepeodeul
coolingfans
•••
•
Column oven
temperamre
sensing
probe
(thermocouple)
•
Heated
detector
1L---.,--!i-:-1W
mOUDling block
Dual
iDdepeodeul
oc-coluraa
injectioo
ports
Thick:
insulatioo
between column ovens
G
r·o..
c e c c e oo
Oven
air
circulating fan
~~
Stainless steel
wire
mesh
llig!><>utpul
heating
element
DIAGRAM OF DUAL COLUMN OVEN-EQUIPPED 8610C GC C/lASSlS
For certain special applications, the SRI 8610C gas chromatograph chassis may
be
fitted
with
dual, independently-programmable column ovens. Dual column ovens
permit
a single 8610C
gas
chromatograph to perform
two
separate, unrelated analyses simultaneously
with
independent start
times and temperature programs. The immediately apparent advantage to having a GC equipped
with
two
column ovens is the
ability,
for instance,
to
perform adirect
on-column
injection ofaBTEX
sample onto a capillary column and flame ionization detector
(FlO)
using a temperature
program,
such as 50' C to 200' C at a temperature ramp of 10'C per minute, while
also
performing a
gas
analysis by
direct
on-column injection ateither anisothermal
temperature
orata low-level
temperature ramp, onto a packed column connected to a thermal conductivity detector (TCD)
in
one
column oven. By
placing
one temperature program onchannell for
the
FIn,
and adifferent
temperature program on channel 2 for the TCD, two separate column operating conditions may
be
simultaneously controlled.
A
more
sophisticated method
to
employ dual column ovens
is
multidimensional
gas
chromatography. Briefly, multidimensional GCs permit one sample to
be
analyzed normally on one
column
in
a
main
column oven (connected to a dedicated detector),
with
the ability to "slice" a
timed
segment of the sample elution and place
it
ontothe second
column
in
the second column oven, to
analyze it"under a magnifying glass", of sorts. The first column effluent is
directed
momentarily onto
the second column and oven, where this "injection" is separated byamuch longer, lower temperature
column and second detector, providing awell-separated close-upof the time segment slice.
