Drilled GC inlet liner - purpose?

Discussions about GC-MS, LC-MS, LC-FTIR, and other "coupled" analytical techniques.

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In the midst of developing a method for low-level PAHs by 8270 and I noticed that Restek recommends their drilled uniliner (hole near top, with wool.) What is the purpose of the hole in these liners?
The uni-liner will minimise the number of active sites in the sample pathway so less adsorption occurs. This allows a better recovery for the active analytes in your sample.

Hope this helps.

Please see presentation below:


There is good explanation for this liners design.


Tomasz Kubowicz
The Uniliner attached to the head of the column so it acts similar to a direct injection into the column. The drilled hole is to allow gas flow and pressure regulation to work properly since this is installed in a standard split/splitless inlet. It also allows for the liner to be swept with gas once the end of the splitless phase has occured.

Without the hole the GC can not control the column flow since is it set up to control the pressure after the injection port instead of before the injection port. These are back pressure regulated instead of head pressure regulated like the older direct inlets were.
The past is there to guide us into the future, not to dwell in.
Ahh, I think I get it now - since the capillary column itself seals tightly with the uniliner, you need to create a new opening to the liner to allow split gas flow. Chalk it up to my poor understanding of the mechanics of split injections. Thanks all for the replies.
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