Switching from Helium to Nitrogen Carrier Gas for GC by Switching from a 30m x 0.25mm x 0.25µm Column to a 20m x 0.15mm x 0.15µm Column

Our own Jaap de Zeeuw is a master chromatographer and he sometimes does his best work while sleeping.  Recently he was sharing with me an idea that woke him up in Singapore at 3 AM about switching from helium carrier gas for GC, which is still under threat from a supply shortage, to nitrogen, an abundant gas.   This “dream” Jaap had was to use nitrogen and get the same efficient separations as helium delivers while using exactly the same oven program rate to get the same analysis time.  I’d call that a fantasy, until Jaap demonstrated with the EZGC Method Translator how it could be done.  This got me excited enough that I gave up my weekend to do the necessary lab experiments using GC-FID on fragrances, including the one in the example below.

Essentially, operating a 30m x 0.25mm x 0.25µm Stabilwax at helium efficiency-optimized flow and optimal heating rate and a 20m x 0.15mm x 0.15µm Stabilwax at just below nitrogen speed-optimized flow (matching the holdup times with the Method Translator) allows you to use the same oven program rate and deliver the same looking chromatograms in very close to the same time!

Nothing comes for free, so sample loading capacity is about 5x less for the 0.15mm versus the 0.25mm column, but the concept works and I will continue to explore its implementation in my lab.

Keep on dreamin’, Jaap!