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5
Micro GC Channels
Tuning the backflush time on a HayeSep A channel
Tuning the backflush time on a HayeSep A channel
For each new HayeSep A channel with a backflush option, it is necessary to tune the backflush
time properly. The tuning procedure of the HayeSep A channel is different than the tuning
procedure of other channels.
The goal for tuning the backflush time for the HayeSep A channel is to get all peaks of interest,
components up to propane, on the HayeSep A column while all unwanted peaks that elute after
propane are backflushed.
Tuning procedure for HayeSep A channel
1 Set the backflush time of the HayeSep A channel to 0 seconds.
2 Set an appropriate run time for the first analysis (for example 300 seconds or longer).
3 Analyze the NGA Gas Calibration standard, and identify all components in the calibration
standard.
4 When all peaks of interest are identified, select a proper backflush time after propane peak.
Figure 30
propane peak elutes around 90 seconds, proper backflush time for the HayeSep A here is around
120 seconds.
Consider that the total run time must be sufficient to backflush all unwanted components from
the column. The ideal total run time is approximately twice the backflush time or higher. So in this
example, a total run time of 240 seconds is sufficient to backflush all unwanted components from
the HayeSep A channel.
100
80
60
40
20
10
20
30
Figure 30.
Selecting backflush time for a HayeSep A channel
To disable backflush
To disable backflushing, set the backflush time to 0. This puts the system in normal mode during
the entire run.
78
shows an example of the tuning procedure of HayeSep A channel. In this example, the
Peaks of Interest
40
50
60
70
80
Appropriate
Backflush Time
90
100
110
120
Seconds
Unwanted Peak
130
140
150
160
170
Agilent 990 Micro GC User Manual
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