4 Installing 7890 GC Columns
Columns
78 5977B Series MSD Operating Manual
Columns
Many types of GC columns can be used with the MSD, but there are some
restrictions.
During tuning or data acquisition, the rate of column flow into the MSD should
not exceed the maximum recommended flow. Therefore, there are limits to
column length, diameter, and flow. Exceeding recommended flow results in
degradation of mass spectral and sensitivity performance.
Remember that column flows vary greatly with oven temperature. (See“To
Calibrate Column Flow Linear Velocity in a 7890 GC” on page 95 for
instructions on how to measure actual flow in your column.) Use the Flow
Calculation software and Table 7 to determine whether a given column will give
acceptable flow with realistic head pressure.
Table 7 Gas flows
Feature Gas flows
High vacuum pump Diffusion Turbo
Optimal He column flow mL/min 1 1 to 2
Maximum recommended gas flow mL/min
*
* Total gas flow into the MSD: column flow plus reagent gas flow (if applicable) plus JetClean H
2
flow (if
applicable). Based on helium gas use. For other gases the maximum flow will vary.
1.5 4
Maximum gas flow, mL/min
†
† Expect degradation of spectral performance and sensitivity.
26.5
Max column id 0.53 mm
(30 m)
0.53 mm
(30 m)
CI capability No Yes
CI reagent flows, mL/min NA 1 to 2
JetClean option H
2
flow NA 0.4 mL/min
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