32 Installation and Operation Guide
3 Splitter Configurations
Restrictor id and length
1 Run the Effluent Splitter Calculator and enter the following information.
The calculator provides a list of possible restrictors.
• Column flow. Use the ChemStation, GC, Flow Calculator, or Method
Translation Software to determine the column flow in mL/min (with the
column outlet at 3.8 psig) at the initial oven temperature.
• Initial oven temperature. This is the temperature setpoint for an
isothermal method or the initial temperature for a programmed method.
• Carrier gas type. Enter Helium, Hydrogen, Nitrogen, or Argon.
• Detectors 1 and 2 operating pressure (psia). The operating pressure
must be in absolute units. Most detectors (FID, TCD, ECD, NPD, and
FPD) operate at atmospheric pressure (14.696 psia). Exceptions are the
MSD (0 psia) and AED (16.196 psia).
• Flow Ratio of Detector 2 to Detector 1. This is the desired split ratio
between the two detectors. Usually this number is 1, meaning the
effluent divides equally between the detectors. This can be adjusted to
higher values, but should normally not exceed five.
• Splitter (column outlet) pressure (psig). This is the desired pressure at
which the splitter (and thus the end of the column) will operate. It can be
set between 2 and 4 psig, but is usually set to 3.8 psig. This number can
be varied to obtain an acceptable combination of restrictors that will
have sufficient flow velocity to give good peak shapes.
2 Choose the id tubing that gives a length closest to (and at least) 0.3 m for
most detectors and 0.8 m for MSDs. The green fields with tubing diameters
in mm can be edited if you have other sizes of deactivated tubing available.
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