Introduction and Initial Operation
Varian, Inc.
User Manual Micro-GC
Page 29
Conditioning of Molsieve columns
On a properly activated column nitrogen and oxygen will be very well separated.
However, in time you will find that these two peaks will start to merge together. This is
caused by water, present in the sample or carrier gas, adsorbing to the stationary
phase. To restore the columns efficiency it will suffice to raise the oven temperature to
180
C (max. column oven temperature) and, with the normal operating pressure on the
column head, leave it to condition for about an hour. You are advised to switch the
detector filaments off during this period. After reconditioning you can test the column
performance by injecting plain air. If you have a proper separation between nitrogen
and oxygen again the column separation power has been restored. If the Micro-GC's
frequency of use is very high, you might adopt a standard reconditioning procedure of
leaving the instrument with the oven temperature at 180
C overnight. The longer the
re+onditioning period the better the column performance without damage.
Summary of Contents for Micro-GC 490-GC
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