64
GC Injectors
10-Port GasSamplingValvePlumbingOptionExamples
LOAD
INJECT
CARRIER
IN
SAMPLEIN
SAMPLE
OUT
LOOP
TO
COLUMN
CARRIER
IN
SAMPLEIN
SAMPLE
OUT
LOOP
TO
COLUMN
SIX-PORTMODE
BACKFLUSH
INJECT
CARRIER
IN
SAMPLEIN
SAMPLEOUT
LOOP
DETECTOR
COLUMN
LOAD
CARRIER
IN
SAMPLEIN
SAMPLEOUT
LOOP
DETECTOR
COLUMN
DUALLOOPS
INJECT
CARRIER
B
CARRIER
A
COLUMN
A
SAMPLEIN
SAMPLEOUT
COLUMNB
LOOPS
B
A
LOAD
CARRIER
B
CARRIER
A
COLUMN
A
SAMPLEIN
SAMPLEOUT
COLUMNB
LOOPS
B
A
CARRIER
IN
SAMPLEIN
SAMPLEOUT
DETECTOR
LOOP
MOLESIEVE
COLUMN
SILICAGEL
COLUMN
MG#1
INJECT
The valve plumbing coniguration
shown at right is the standard 6-port
coniguration. The sample loop
connected between ports 3 and 10
is inserted into thecarrier gas stream
when the valve is rotated to the
INJECTposition.
The same 10-port valve can also
be conigured to backlush the
column when the valve is rotated.
Backlushingcanoftenshorten the
analysis by eliminating the need to
program the column temperature
up to elute highboiling analytes.
A single 10-port valve can be
plumbed to inject the same sample
onto two separate columns using
two separate loops.This is especially
useful where two different carrier
gas types are used, or where the
detectors employed have very
different sensitivities and need
different sample sizes injected.
The10-port valve coniguration shown at right
is our Multiple Gas Analyzer #1 (MG#1) valve.
In the LOAD position, the sample loop is illed
withnewsamplegas,and theSilicaGelcolumn
is downstream of the MoleSieve column. In
the INJECT position (shown), the contents
of the loop are lushed into the Silica Gel
column, which is now upstream. The lightest
analytes blow through onto theMoleSieve for
separation. The valve is then rotated back to
the LOAD position, just prior to the elution of
ethane for the separationof C
2
-C
6
.
