Early spikes in FID chromatogram

Chromatography Forum: GC Archives: Early spikes in FID chromatogram
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Wednesday, March 24, 2004 - 01:19 am:

I have a DB5 equivalent column using helium and a FID. I have started to notice low level spikes and noise in the baseline at the very front of the ramp (70degC) and they disappear as soon as the solvent front reaches the FID - the peaks might "disappear" under the column bleed.
Has anyone found this before - as a new nozzle/jet is $450 and a new collector is $1000.
Might it be the column (6mnths old - 1000 clean samples).
Any help would be great!

ps I have good air and hydrogen


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Bernd Mischke on Wednesday, March 24, 2004 - 04:04 am:

Hi Anon,

send me an chromatogram in an exchangeble format like *.cdf (AIA-format) and I will try to help You.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Thursday, May 6, 2004 - 03:25 am:

I have solved this problem with some help - its seems to be noise generated by autosampler vibration when post injection cleaning.

Anonymous


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Wednesday, May 12, 2004 - 07:25 am:

If the noise is caused by vibration there is probably a loose connection in the signal processing circuitry somewhere. Vibration alone will not cause the problem, so if you have not found the component the vibration is affecting the problem may not be completely resolved and may reappear and be more serious in the future.

This isn't meant to be negative, just to help prevent future problems.


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Thursday, May 13, 2004 - 12:54 am:

I have been advised that the FID needs an add-on kit containing copper tube to connect into the H2 which helps out the H2 electronic flow control module.


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