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Maximum and minimum flows
The maximum suggested flow for MSDs depends on the vacuum pump used.
For diffusion pump and standard turbo systems, the flow should not exceed
2 mL/min. For performance turbo systems, the flow should not exceed
4 mL/min. These flow limits restrict the column flows and split ratios that can
be used with MSDs.
Try to have the flow through each restrictor tube at least equal to the
suggested minimum flow in
work, but peak broadening and/or tailing may result.
Table 4
Restrictor internal
diameter, mm
1 The makeup flow is listed in cell B 36 of the effluent splitter calculator. You
2 Use the Column Pressure/Flow Calculator to determine the flow through each
Installation and Operation Guide
Suggested minimum restrictor flows
Helium
0.10
0.400
0.18
0.720
0.20
0.800
0.25
1.000
0.32
1.280
0.45
1.800
0.53
2.120
should have at least 0.5 mL/min for stable pressure regulation. Note that
this value will decrease as the oven temperature programs up.
restrictor at the maximum oven temperature of the method, add them and
subtract the calculated column flow at that temperature. This value should
be greater than 0.5 mL/min.
Table
4. Restrictors that have less flow will still
Minimum carrier gas flow, mL/min
Hydrogen
Nitrogen
0.500
0.125
0.900
0.225
1.000
0.250
1.250
0.313
1.600
0.400
2.250
0.563
2.650
0.663
Splitter Configurations
Argon
0.110
0.198
0.220
0.275
0.352
0.495
0.583
3
33
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