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clicking the Insert or Delete point buttons. The Insert button
allows you to add a single point when you click on the gradient
profile. Repeat this action to add more points. The Delete
button allows you to remove a single point when you click on
it.
Note that only the portion of the gradient that has not yet
occurred during the run can be modified.
6.4.7 Bypassing the Solid Load Cartridge
(Rf+ systems, including those equipped with 4x)
Occasionally, impurities precipitate in the solid load cartridge
as compounds are purified. This may cause high back
pressures resulting in reduced flow rates and long run times.
Clicking this button changes the injection valve position,
which removes the solid load cartridge from the solvent path
and relieves the back pressure.
CAUTION: Bypassing the solid load cartridge too soon during the
purification run may leave desired compounds on the solid load
cartridge. After removing the cartridge from the fluid path, these
compounds cannot be purified.
If you need to use this feature, perform the following to ensure
that you do not leave desired compounds on the cartridge:
1. Run a TLC plate prior to starting the run. Measure the Rf
(retention factor) of the slowest eluting compound of
interest. (The Rf should be between 0.2 and 0.8 — the same
range used by the G
Percent B solvent used to run the TLC plate. If a compound
displays tailing peaks as streaks on TLC, the Rf used
corresponds to the bottom of the streak.
2.Load the Sample in the Solid Load Cartridge and note the
cartridge size. Refer to list below to determine the cartridge
volume. If the cartridge is partially filled with silica, use
the cartridge volume as if the cartridge were completely
filled with silica.
• 5 gram cartridge = 10 mL volume
• 25 gram cartridge = 45 mL volume
• 65 gram cartridge = 110 mL volume
Section 6 User Help Reference
CAUTION
O
RADIENT
PTIMIZER [6.3.3]
). Note the
6-55
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