160 Advanced Operation Manual
4 Columns and Oven
Backflushing when connected to an MSD
If using an MSD with the GC, backflushing becomes more
complex. Set up backflush as a post run event by using the
Backflush Wizard present in the MSD Productivity
ChemStation.
Backflushing using a capillary flow technology device
Because the following capillary flow technology (CFT)
devices connect to a controlled carrier gas supply, they can
be used to backflush a column:
• G2855B Capillary Flow Technology Deans Switching
System
• G3180B Capillary Flow Technology Two- Way Splitter
(with makeup gas)
• G3183B Capillary Flow Technology Three- Way Splitter
• G3185B QuickSwap Accessory
A conceptual diagram for a simple setup is shown in the
figure.
After the last analyte of interest elutes, you can program a
decrease in inlet column flow with an increase in the
pressure/flow from the Aux EPC or PCM connected to the
CFT device, thereby reversing column flow and forcing the
remaining analytes off the column and out of the inlet split
vent. You can do this using a post run program or as a
ramped pressure or flow program.
Split Vent
Tra p
Inlet
Column
CFT Device
Auxiliary
EPC/PCM
Detector