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The MSD ChemStation will not accept an outlet pressure entry greater than
4.0 psig. This does not mean that higher pressures cannot be set for
QuickSwap; it is merely a current limitation of the algorithm used to calculate
column flow rate. If running in constant flow mode, it is imperative that
QuickSwap pressure and column outlet pressure are ≤4.0 psig for accurate
flow control.
12. Set and Apply the Column Flow
Initial installation
If using one of the checkout methods provided, the column flow is already set.
Continue with
If this is not an initial installation or if not using a provided method, see the
next two subheadings.
Constant flow mode
Unless you plan to backflush the column (see the
Retention Time Locking, we recommend using the Constant Flow mode. It
allows you to choose the desired flow rate and the GC calculates and applies
the necessary pressure. For example, flow rates from 0.7 to 2 mL/min
constant flow may be set with a 100-µm id restrictor depending on pressure
and temperature setpoints.
Constant pressure mode
You must adjust the pressure yourself based, for example, on calculations with
the user-contributed Method Translator utility or through Retention Time
Locking. Constant pressure methods translate well with different outlet
pressures. Proper setting of pressure (such as with retention time locking) will
result in nearly identical retention times for QuickSwap methods compared to
direct-connection methods.
If you intend to backflush the column, you must use Constant Pressure mode.
QuickSwap Installation and Startup
step
13.
Reference
Manual) or use
Overview
29
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