Bypassing The Solid Load Cartridge - Teledyne CombiFlash Rf User Manual

5.4.2 Bypassing the Solid Load Cartridge

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(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 cartridge from the solvent path and
relieves the back pressure.
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
of the slowest eluting compound of interest. (The Rf should
be between 0.2 and 0.8 — the same range used by the
Gradient Optimizer [6.3.3]). Note the 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
3. Run the sample and observe the flow rate from the Status
Bar in the upper right corner of the main window. As long
as the system is delivering the programmed flow rate,
there is no need to bypass the cartridge.
4. If the flow rate is slower than that programmed, note the
slowest displayed flow rate. Use the equation below to
determine if the cartridge can be bypassed.
CAUTION
Section 5 Operation
5-13