Operating in Electron Ionization (EI) Mode 3
5975/5977 Series MSD Operation Manual 73
9 Verify that the parameters listed (temperature, inlet and outlet pressures,
and gas type) are those used in the method to determine the holdup time.
Change any parameters that are different than those used in your method.
10 Enter the recorded retention time in the Holdup Time field. Move the cursor
to another parameter’s field and the calibrated column length appears.
11 Click OK to save the changes and exit the dialog.
12 Click OK on the Calibrate Columns dialog to save the calibration.
With capillary columns, such as those used with the MSD, linear velocity is
often measured rather than volumetric flow rate.
Calculation for average linear velocity
Average linear velocity (cm/s) =
where:
L = Length of the column in meters
t = Retention time in seconds
Calculation for volumetric flow rate
Volumetric flow rate (mL/min) =
where:
D = Internal column diameter in millimeters
L = Column length in meters
t = Retention time in minutes
100 L
t
--------------
0.785 D
2
L
t
----------------------------