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Topic: Analytical chemistry  (Read 3963 times)

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Offline Lock

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Analytical chemistry
« on: July 14, 2012, 06:40:21 AM »
Hi I have a question about Gas chromatography

May I ask
what will happen if gas chromatography run is aborted in the middle of GC analysis?

For me my anwser to this is that the the sample residual will be stuck at the column as most of the sample in gas phase has condensated.

Hope you can give me some guidance to this question

Offline JGK

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Re: Analytical chemistry
« Reply #1 on: July 19, 2012, 03:12:04 PM »
If the sample is run Isothermally and you abort the data acquisition then the analysis will proceed as normal (but unseen) unless a further run is started before the analye leaves the column and passes into the detector.

If you are running a thermal gradient method and abort it the settings will revert to the time=0 conditions. Analytes held within the stationary phase will continue to elute but at a very slow rate. If you run anther sample before everything has eluted from the column system you may well see additional peaks in the next chromatogram which could be a problem if the sample has multiple analytes.
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Offline Jasim

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Re: Analytical chemistry
« Reply #2 on: July 24, 2012, 01:27:11 PM »
If you have a problem because of this I recommend cranking up the temp and 'baking' the column at it's maximum isothermal point - usually around 200-250 Celsius, but it varies from type to type, so check the manufacturer's info because heating a column too high and/or for too long will damage it permanently. Keep the heat up for about 1-2 hours, make sure the flow stays ON during this time. That will flush the column out and should get rid of any residual contamination hanging around.

Also, could you please try to give a little more descriptive title to your threads.

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