Reference
Page 70
User Manual Micro-GC
Varian, Inc.
The standby mode for the is to be in the backflush configuration (if the instrument is
equipped with the optional backflush valve).
Back flushing will ensure that the pre-column will be in good condition for the next run.
Tuning
Tuning of the backflush time is done by trial and error. Reducing the backflush time will
transfer fewer compounds to the analytical column.
How to Tune
Obtain a chromatogram in foreflush. Check out the retention times of the compounds
you have to quantify. Start at a backflush time of 10 seconds. Obtain a second
chromatogram. Adjust the Backflush time (increments of 0.1 seconds are possible) until
all components of interest are transferred to the analytical column and that all unwanted
peaks are backflushed.
Be aware that a small pre-column is used. It is not always possible to cut between 2
peaks!
Backflush Time range 0.5 seconds until maximum run time.
Special value
BACKFLUSH TIME = 0 this puts the system in FOREFLUSH mode during run the entire
run.