World Record Set for Longest Gas Chromatography Retention Time!

My colleague Jaap de Zeeuw holds a Guinness World Record certificate for making and applying the longest GC column ever, 1300m.  That’s quite a feat and I’ve often wondered what the retention times were for that column when you consider the holdup time was probably on the order of hours instead of minutes.  No matter how long the retention times were though on that 1300m GC column, I may have exceeded them on a simple 30m x 0.25mm x 0.25µm Stabilwax, which I’ve been using for a selectivity study conducted by colleagues James Harynuk and Teague McGinitie at University of Alberta.  This work will be presented at the 11^th GCxGC Symposium (and 38^th International Symposium on Capillary Chromatography) in Riva del Garda, Italy.

The study includes, Rxi-1ms, Rxi-17Sil MS, Rtx-200, and Stabilwax GC columns, which represent a variety of stationary phase polarities and selectivities.  The first 3 have temperature stabilities of 350, 360, and 340°C, respectively, but the Stabilwax only goes to 260°C.  I can chromatograph all of the molecules chosen for the study on the first 3 phases, but when I get to the polycyclic aromatic hydrocarbons (PAHs), some of which are notoriously involatile, I struggle on the Stabilwax.

The first figure below shows the Acquired Sample list for the Stabilwax work, and I purposely started with SV Calibration Mix #5 / 610 PAH Mix because I knew some of the compounds would be hard to elute from the wax GC column.  Well, how about almost impossible to elute?  As you can see in the first chromatogram, even though I had a 40 min final oven temperature hold time at 250°C, none of the PAHs with molecular weights of 252, 276, and 278 eluted.  In chromatogram 2, which is run 3 from the queue, I see carryover peaks for 252 PAHs (benzofluoranthenes, benzo[a]pyrene), but still didn’t get complete elution of the PAHs even though I pushed the final hold time up to 90 min.  OK, this isn’t going so well, this part of the selectivity study…

Eventually, after uninstalling the Stabilwax column, putting it in my office for a few days, and then reinstalling it to run different standards, I finally saw the first 276 and 278 PAHs eluting as massively broad peaks, almost 5 min wide at base.  When I calculate retention time (yeah, sure, I included the time in my office!) for indeno[1,2,3-cd]pyrene, it’s 7.25 days!

Your move, Jaap…