GC Troubleshooting—Tailing Peaks

Description

Our chromatograms can tell us a lot, especially if we focus on the details. Trying to diagnose and correct tailing peaks are one area where special attention to the chromatogram can be particularly helpful. We take a look at some of the causes of tailing peaks, which are a very common problem, and how our chromatogram may be giving us clues to their cause. 

Additional Resources

• Why do only some of my peaks tail?

Restek Recommended Tools & Parts

• Topaz Inlet Liners

Transcript

Hello, everybody, and welcome to another Restek Tip. In this video, we’re going to talk about tailing peaks, something we’ll often encounter when we’re doing gas chromatography. Now, tailing peaks can typically have one of two causes. Either we have some type of disruption to our flow path, or we have some type of reversible chemical adsorption going on. But how do we tell the difference? The first thing we want to do is take a look at our chromatogram. If most or all of our peaks are tailing, that type of indiscriminate tailing is often caused by a flow path disruption, something that can affect all of the compounds present. Conversely, if only a select few of our peaks are affected, it very well could be due to some type of chemical behavior, some type of adsorption or interaction due to a specific compound or compound class.

So, now once we’ve sorted that out, what can we do to remedy those problems? Well, in the case of a flow path problem, what we want to do is make sure all of our installation distances are correct, make sure our column cuts are square, and all of our connections are leak free and ideally have as little dead volume as possible. On the cleanliness side of things, the chemical absorption side of things, we want to make sure everything is clean and inert. So, it may be time to do some maintenance – replace our liner, replace our inlet seal, maybe trim a little bit off our guard column, anything that we can do to make sure that the whole flow path is clean and well deactivated so there’s little chance of any interactions occurring. So, those are really the two approaches that we have to address the root causes that are behind most of our tailing problems. Thank you very much for joining us for this Restek Tip.