HeadSpace Tailing

Discussions about GC and other "gas phase" separation techniques.

5 posts Page 1 of 1
Hi all:

We have a Scion/Bruker GC456, with a HeadSpace autosampler SHS-40. The GC has a FID detector.

We are injecting an OVIS STD. (We prepare it with Methanol, Ethanol, Acetone, IPA, Diethylamine, Ethyl Acetate, Triethylamine)

The problem here, is that after a weekend the amines started tailing much more than before.

We have trim the column, heat the HeadSpace valve an d transfer line, changed the liner, clean the injector and detector ports, changed the column.

Any one know what can be happening???
Not familiar with your unit, but the injection pulse may be too long. If it is a sample loop type unit, all the time needed is 3-5 loop volumes.
Depending on your configuration, you may be able to test the GC side of thing separate from the HS side of things. If you have a regular split/splitless inlet with the HS transfer line spliced into the inlet carrier gas line (a common setup), you can inject directly into the inlet. If you do this and your tailing is still excessive, you can focus on the GC side of things; if the tailing goes away, it may be the HS unit or HS transferline. In addition to checking that your injection time is reasonable, also look at your zone temperatures. Consider also checking with your manufacturer whether a fused silica transferline can be used instead of steel as adsorption may be to blame here if you can't get the transferline hot enough or have unheated zones (https://blog.restek.com/?p=27110).
If you cannot find a solution to the issue (especially if no settings have been changed on the GC) contact Scion support who are very efficient and will be able to offer detailed help.

Provide them with as much detail as possible

Do you use any high-level preconditioning standards or concentrated amine standards to prime your system before each run? This can sometimes help by saturating active sites.

What kind of column are you using?
5 posts Page 1 of 1

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