Agilent Technologies G3183B, Инструкция по установке и эксплуатации

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28 Installation and Operation Guide
3
Splitter Configurations
The column flow at 200 °C should be no more than 2 mL/min. This becomes
important when the column is run in constant flow mode. If constant flow
mode is used with
Configuration 1
and the method programmed to 300 °C, the
column flow should not exceed 1.13 mL/min ([0.71 + 0.71 + 0.71] –1).
For constant pressure methods, first find the maximum flow as above. Use the
GC, ChemStation, Flow Calculator Software or the Method Translation
Software to find the inlet pressure that gives the maximum flow at the upper
temperature of the method (make sure the column outlet pressure is set to
3.8 psi for the calculation).
For example, if a 30 m × 0.32-mm id column is used with
Configuration 1
, using
helium carrier and programming to 300 °C, the pressure that gives a flow of
1.13 mL/min is 28.4 psig. This is the maximum pressure at which the inlet
should be set. The inlet should not be set at or below 3.8 psig.
The performance turbo on the MSD is preferred because it allows splitter
configurations with higher permissible column flows.
Configuration 2 is set up
for the performance turbo and allows almost three times the column flow
([1.42 + 1.42 + 1.42] – 1) = 3.26 mL/min at 300 °C).
If you decide to use a typical configuration, note the restrictor dimensions
from
Table 2 and proceed to “Restrictor and Column Installation" on page 35.
Splitting to an MSD
Note that the maximum column flows for an MSD are quite low. This limit is
imposed by the rating of the turbo or diffusion pump. Configurations with
split ratios greater than 1 can be used but peak broadening and/or tailing may
occur if the flows to the other detectors becomes too low.
In practice, the column flow can be set to within 0.5 mL/min of the total flow
if necessary.
Split ratios to the MSD greater than 1 are very limited due to these flow
considerations and should be avoided if possible.