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 temperature start with good focusing for naphthalene, the most volatile PAH. And the Rxi-5Sil MS stationary phase (5% phenyl type) is silphenylene, a backbone modification that provides a faster separation for benzo[b]fluoranthene and benzo[k]fluoranthene versus a typical 5% diphenyl column like the Rxi-5ms.
In addition to the speedy separation of the benzofluoranthenes, note the almost baseline separation for indeno[1,2,3-cd]pyrene and dibenz[a,h]anthracene. Not bad!
Although you’ll see literature that encourages faster GC analyses through employment of smaller inside diameter columns, I prefer the 15m x 0.25mm x 0.25µm due to the better sample loading capacity for the 0.25mm x 0.25µm over something like 0.18mm x 0.18µm or 0.15mm x 0.15µm columns. In addition, the larger ID column has better ruggedness than the smaller bore columns.
One more note on the use of 15m x 0.25mm x 0.25µm versus 30m x 0.25mm x 0.25µm columns. Under vacuum-outlet conditions, i.e., using MS, the analysis time is about 3 times shorter for the 15m column. You can prove that to yourself with the EZGC Method Translator and Flow Calculator.
