Selection of GC Modes

[vdnsrinivas]

Hi,

How we need to select the inlet mode @ constant pressure mode or constant flow mode??
How we need to select the Injection @ pulsed split and pulsed splitless??

Thanks,
Sri

[Don_Hilton]

There are reasons for selecting each - and knowing what you are tring to accomplish could help with the suggestion.

If you are just settign parameters to see what the GC will do, select constant flow mode and no pulse with the injection.

Split or splitless depends entirely on the samples. Split is good for samples where the analytes are in the parts per thousand range, splitless for samples in the parts per billion range.

[Johnny Rod]

Use constant flow mode if you can. This tries to maintain the same flow at all oven temperatures, so keeps you closer to the same linear gas speed all the time. If you are using a temperature ramp thenthe run time is shorter and the later peaks sharper than if you use constant pressure mode. Old manual GCs were constant pressure.