HTA HT2800T - Page 138

HT2800T_en_c.doc Page 138 of 275
system, watch the GC. Count the time between the start of the first run and when the GC
becomes Ready for the second run, then add 1 minute.
You can also estimate the analysis time without making a run. By adding the GC oven program
duration and the duration of any post-run programs, you can get close to the true cycle time.
Also consider time for data processing. While in most cases data processing is not a problem, a
very busy Data system may need extra time between samples.
To validate the analysis time, look at the GC run time. The analysis time cannot be less than the
total run time. Then look at the GC post run program duration. The analysis time cannot be less
than the total run time plus the post run program duration.
Finally, consider that the GC cooling time may vary according to room temperature: the higher
the room temperature is the more time is needed for the GC cooling time; typically it implies a
shorter time during winter seasons and a longer time during summer seasons. Therefore, the
analysis time should be set according to the worst scenario (summer season).
5.1.2.2 Advanced parameters
Access sequence: RUN>SETTINGS>METHODS>METHOD X>ADVANCED
The following parameters can be viewed/edited:
• Enrichment Cycle(s): the number of enrichments in the injection cycle. The enrichment
allows the user to inject a higher quantity of sample.
NOTE. It is only possible to enrich the sample by multiple injections if the gas
chromatograph can support this feature by a proper trapping system.
• Dwell Between Injections: delay time between any enrichment, to allow the Headspace
vial to equilibrate.
Select “Exit” to exit from this screen and return to the “RUN: METHOD X” screen (see
paragraph 5.1.2 “Method X: Setting method parameters”“).
5.1.2.3 Preparation parameters
Access sequence: RUN>SETTINGS>METHODS>METHOD X>PREPARATION
The following parameters can be viewed/edited:
• Syringe Temperature: temperature of conditioning of the syringe. This value can be
between 40°C and 150°C (active conditioning) or off (inactive conditioning);
• Oven Temperature: temperature of conditioning of the oven. This value can be between
40°C and 170°C or off (inactive conditioning);
• Incubation: sample incubation time inside the oven;