Archive for the ‘GC Injection Techniques’ Category

Upcoming Restek Cannabis Testing Seminar

10/9 UPDATE- This seminar has been cancelled. Stay tuned for future dates.  New to chromatography? Looking to brush up on your current analytical skills? Interested in what different types of cannabis testing currently exist? The analytical market for cannabis is a rapidly growing, burgeoning field. As more and more states legalize cannabis, an increased number […]

Troubleshooting Injection Volume Variation in the Concurrent Solvent Recondensation – Large Volume Sample Injection Technique

I’ve started receiving a number of questions about the large volume injection technique called Concurrent Solvent Recondensation – Large Volume Sample Injection. Most recently, a question came through the Tech Service group about injection volume variation. I had encountered a similar problem when working on the 50 µL injection for the combined 1,4-Dioxane and Nitrosamines (EPA […]

An introduction to the benefits of using split injection when performing semivolatiles analysis by 8270D – the instrument checkout mix

This blog is part of a series; the previous installments can be found here and here. We have mentioned several times that the reduced residence time resulting from the fast sample transfer that occurs during a split injection reduces in-inlet degradation and adsorptive loss. Proof of this can be seen in the first run of […]

It May be Hot Outside, but Your Headspace Analysis Can Still Suffer from the Cold

Summer days are my favorite – hot, sunny, and full of fun. But one thing that’s really not fun is trying to track down contamination and/or carryover in your headspace-GC (HS-GC) system. I get questions about this topic pretty regularly, so I thought I would post a blog on the most common culprit for contamination […]

Shoot-and-Dilute GC – The exciting world of split ratio

OK, maybe it’s too much to hope that split ratio is exciting, but I think the information I’m laying down, all based on data I’ve recently collected in the lab, can be helpful to anyone working with GC. So please check out my recent article in The Column. Let me know if you have any […]

Split Injection Makes for Easier Polar Solvent GC Work versus Splitless Injection

As anyone who’s doing QuEChERS knows, analyzing acetonitrile extracts on nonpolar GC columns (like Rxi-5ms, e.g.) using splitless injection can be problematic because of the classic solvent – stationary phase mismatch.  To avoid split peaks we usually have an initial GC oven temperature slightly above the 82°C boiling point of acetonitrile (MeCN), but this causes tailing […]

Don’t Forget to Change Your GC Inlet Bottom Seal and Trim Your GC Column as Part of Your Maintenance Routine!

While doing PAH analysis for dirty samples with splitless GC I saw increased peak tailing and loss of response, so I did what anybody would do: changed my GC inlet liner.  In this case I used a Restek Premium single taper inlet liner with wool.  Unfortunately when I did my next standard analysis, not much was improved.  […]

Fast Analysis of PAHs using Split Injection and a Short GC Column

Click on the this link:  Fast Analysis of PAHs  to see how I analyzed the EPA 16 polycyclic aromatic hydrocarbons (PAHs) in under 10 min using GC-MS by employing split injection with a Restek Premium Precision split liner with wool and a 15m x 0.25mm x 0.25µm Rxi-5Sil MS GC column.  Split injection allows a higher GC oven […]

Shoot-and-Dilute GC – Practical GC – The Column

Check out my recently published articles in LCGC – The Column on Shoot-and-Dilute GC (split injection GC), where I outline the benefits of this technique through recently collected experimental data in my lab at Restek.  I’m two articles into my Practical GC series, with another one soon to be published.  This is a continuation of other split injection work […]

A quick evaluation of some disadvantages to performing semivolatiles analysis by EPA Method 8270D with splitless injection

This blog is part of a series; the previous installment can be found here. Semivolatile calibrations on the 30 m x 0.25 mm ID x 0.25 µm df column format often range from 1.0 to over 100 ng/µL; however, a 0.25 mm ID column usually experiences peak overload as the mass on column approaches 10 […]