12 Injection Port
12.5 Split/Splitless Injection System
138
GC-2010 Plus
12.5.9 High pressure injection splitter mode and back flush
Q High Pressure Injection
High pressure injection is a split/splitless injection method which keeps the column inlet
pressure at a value higher than the analysis pressure for a specified period of time while the
sample is injected. Then, the column inlet pressure returns to the normal analysis value.
High pressure injection is effective especially for the splitless injection system. High
pressure injections, can reduce the total gas volume and improve percent recovery valves.
Sensitivity may be improved by reducing adsorption by increasing the speed of transition to
the column and by increasing the injection amount in some cases.
NOTE Although it is usable for split analysis, note that the split ratio is different from the set value at high
pressure injection.
Q Splitter Fix
If the injected sample consists of a solvent with a high vaporization expansion coefficient, the
pressure inside the injection port drastically increases when the solvent vaporizes. As a result,
ESC may operate to lower the inlet pressure which is higher than the set pressure and too
much sample components may be discharged from the split vent, reducing sensitivity.
In the splitter fix mode, the voltage on the split flow valve is fixed right before the injection of
the sample, which prevents the discharge of the sample at more than the specified split ratio.
NOTE When the splitter fix state is kept for a long time, the pressure cannot be maintained at a specific level
and analysis cannot be performed with good reproducibility.
To use the splitter fix mode during manual injection, it is recommended to turn it on after the ready
state, inject the sample in certain intervals, and start analysis.
Q Back Flush
Back flush is a method to discharge a component that usually takes a long time to elute from
the column in a short time by blowing it back into the column inlet. For using the Back Flush
mode, a back flush element* (optional) is necessary. For details, refer to the instruction
manual of back flush element.
*P/N: 221-72484-92
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