Table of Contents
Advertisement
+
CombiFlash® Rf
User Manual
Enable Run Length Extension – When enabled, this option
automatically extends the run if a peak is eluting at the end of
the maximum %B gradient. This ensures that a late-eluting
peak fully comes off the column and is collected.
An automatic run extension is a five-minute isocratic hold
added to the end of the run's maximum %B gradient profile.
During the extension, the system continues to pump the
maximum %B solvent mixture. Should the system still detect
a peak after an extension, the system will add another, up to a
maximum of three extensions.
Occasionally, compounds might come off the column once the
%B returns to the minimum value at the end of a run. If the
Run Length Extension is enabled, it will automatically extend
the run one time to clear the column and plumbing of any
remaining material.
Original method
0
5
Figure 3-9 Automatic Run Extension Examples
Figure 3-9 illustrates the possible run extensions. The original
method was programmed to rise to the maximum %B over
seven minutes, hold for two minutes and return to the
minimum %B for a final minute. At nine minutes, a peak was
eluting. The system extended the run, holding the %B at the
maximum level for another five minutes. This also occurred at
fourteen and nineteen minutes, resulting in the second and
third extensions. At 24 minutes, the %B solvent strength
returned to zero. Before the final minute elapsed, more
compound was detected, causing the system to extend the run
for a final five minutes at the minimum %B.
3-16
Extension 2
Extension 1
10
15
Minutes
Final Extension
Extension 3
20
25
Advertisement
Table of Contents
