Make-up with FID

Chromatography Forum: GC Archives: Make-up with FID
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Friday, August 22, 2003 - 07:28 am:

everybody here use make-up gas in FID ?
My sensitivity falls so much if I take off the nitrogen?


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Friday, August 22, 2003 - 09:25 am:

It is quite common, with capillary columns almost a necessity.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Friday, August 22, 2003 - 12:32 pm:

Original Anon,
Make sure to check the instrument manual for the right total flow, this can make a dramatic difference. Also I have seen that nitrogen gives a bit more sensitivity than helium does also. And one last suggestion, make sure you have the right jet for the size cap column you are running, some instruments use different dimensions for different cap column dimensions.

Regards,
Mark


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Les on Friday, August 29, 2003 - 08:55 am:

I don't use make-up for simulated distillation. GC uses a 0.53u x 5m x 2.65u HP1 with a flow of around 30cc/min. Plenty of flow outta this baby.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Navaneetha Kannan. on Friday, August 29, 2003 - 10:17 pm:

If you are keeping comparatively higher flow rate, for example about 30 mL/min., no need of keeping the make up gas. But when you make use of columns with 0.32mm or 0.25mm ID, you cannot keep higher carrier flow rate in the column. In such cases, go get higher sensitivity, make up gas is a must.

Navaneetha Kannan.


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