electrical spikes in the chromatogram

[mehtak1]

In my GC - Headspace run some of my injections shows small electrical spikes on the peak itself, it does not effect the integration or the peak area.
what causes random elcetrical spikes

[chromatographer1]

Somebody is running a power drill ( or some electrical device) on the same electrical circuit as your instrument somewhere in the building. The power supply in your instrument or in another instrument is generating noise.
Somebody is tapping your FID with a wrench during the run. Oh, the possibilities are almost endless. Usually the noise producer is within the instrument itself.

Be sure to check your integration carefully to ascertain the values given are realistic.

Sometimes the detector and the electrical connections within it need cleaning or tightening. And then particles can be dislodged after being deposited in the sampling system or in the column itself. These can produce spikes as they elute through the detector.

Good luck,

Rod

[Don_Hilton]

On reading the subject, my first reaction was: dirty FID jet. However, as Rod pointed out, there are many possibilites.

May I suggest 1) check the FID jet to be sure it is clean.
2) assuming that cleaning an FID jet does not solve the problem, post a picture of the GC trace. That may help to rule out a few options.

And if you are using a detector other than a FID, please let us know.

[mehtak1]

thanks guys,
i am using FID and my jet was clean, this electrical spikes we experienced through out out lab randomly, However
it does not compromise my peak area and my suitability was passing through out the run , but it is very hard to convince QA, as they reqiured what causes the elctrical spikes. How can we prove to QA that this spikes are very random and it doesnot compromise any data.

[chromatographer1]

How can you convince anyone of that?

All you can do is present comparative data for each injection that has a spike. (Duplicate the injection)

Good luck with that.

best wishes,

Rod

[Don_Hilton]

I would suggest a power line conditioner. That removes spikes from the electrical line to the instrument -- and saves the instrument from damage. If you can see the spike on the instrument traces, the spikes are hitting components in the instrument.

[larkl]

Are you using a PLOT column? The particles breaking loose and passing through the FID will cause spikes.