Chapter:
Injectors
The On<olumn injeclor is deS'llned
for
,53mm
( wide-bore )
capillary c<>umns
and
118"
pad<ed
~umns
One
0/'
two
on..column
inJf'dot$
can be mounted
on
the
9S1OCGC.
while
a
SIIIQIe
on-ooumn
nJec10r can
lit
on the
Model 310
GC, The
pholo
at
righl shows a singleon.wumn
n;ector mounted
on!l'le 9S1OCGC.
The or>-QOJumn injector is
not
separately
!l'lermostalled
because
rt
closely
follows
!he
te-mpe<ature
of
the
column
0V&rl
due
10
its
lowmass deS'lln and mountiog l0ca–
tion
on ee
wail
of
the
column
oven.
Because
the
insulated
overo
wa~
on SRI
GCs
isonly
,75"
thick.
sample
is Injected
onto
!he
~urnnwe~
,"side fhe column
oven.
SO
no
cold
s~ts
can
trap
the
sam_
Ple,
even
If
the
&le cons"'l$
of
high
bOiling
analytes
Formost appliCatkms. the on–
column injector is the best way to
inject
a
liquidsamplebecause the
syringe deposits the sample into
the
bore
of tne coJumn itself.
The column is usually the
most
in–
ert surface avaitable
( f11Of8
inert
than glass injector liners), and un–
like healed injectors, the sample
does
not undergo
a
"ash vapori–
zation whiCh can broaden peaks
and result in peak tailing. Also,
because the entire
sample is
de–
positedca-cotumn, boilingpoint
discrimination can not occur
as
it
can with
spliVsplitless
injection
techniques,
\.1anl l l ,p"b
Septum
nut
WIth
!i'lil;one
rut>t>e,
septum seals ....'–
her
gas
in, but
anows
S1–
ringe 10penelrate inlO
~umn
60
mete<
,53mm
metal
cap,iary c:olumn shown
c;onneded
to on-ooumn
injector
