Selecting a GC Inlet Liner
Proper sample transfer from your inlet to your column is a critical component of a good gas chromatographic separation. There are many factors that play a role in that sample transfer, and perhaps the first of those is selecting the best liner. Join us as we take a look at what goes on during split and splitess injections and how understanding that can impact our liner choice.
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Hi and welcome to this Restek Tip where we're going to talk about GC inlet liners. Now, I happen to love GC inlet liners. I'm fascinated by this small piece of glass which makes such a big difference in the total quality of our chromatographic analysis. Keep in mind, it's inside the GC inlet liner that the sample, for most of us, is turned from a liquid into a gas and transferred onto the head of the column. Which can make or break an analysis, depending on how that process goes. And so picking the right liner for your application becomes vitally important.
Now, it's an important decision but the good news is there are relatively few choices that will do most of the work for most people. And you're principally going to pick based on the injection technique that you’re using. Let's start with split injections. In split injections the flow through the liner is usually very fast and so that process, that vaporization process, has to happen reproducibly and representatively, really quickly. So it's vitally important that you have wool in that liner to give your sample a chance to stop and vaporize. Especially with the use of autosamplers that inject the sample very, very quickly into the inlet. The wool is often also placed in the hottest spot of the inlet to really promote that volatilization. So a straight through liner with wool is a great choice for most split injections.
Now, on the other side of the coin, maybe you're doing splitless injections. And in splitless mode, the flow through the liner is a lot slower but you really should still use some wool to help stop that sample, when it's injected, and give it a chance to volatilize. Now a single taper with wool is usually a great choice for most splitless injections. It allows the sample to turn into a gas and transfer onto the column again in a reproducible and representative way, despite the fact that the flow is a lot slower. So, straight liners with wool for split injections. Single taper liners with wool for splitless injections. And it's really only if wool becomes a challenge for you that you might want to start to explore some of the other liner geometries that are available. So, I love liners. I hope you love them too and I'm happy that you joined us for this Restek Tip.