GC inlet liner choice made easy

I do GC inlet training seminars every year and the number one question I'm asked is which liner do I use for my work.  We offer a baffling array of liners (including a "baffled liner"!) and it can be difficult to make the proper choice, but after many, many, many hands-on experiments (did I say many?), and limiting the discussion to semivolatile compounds (e.g. PAHs, PCBs, drugs of abuse, hydrocarbons from about C8 to about C44, chlorinated pesticides, organophosphorus pesticides, organonitrogen pesticides, EPA priority pollutants, etc.) and the split/splitless Agilent GC inlet system used with 0.25mm ID columns, I have two liners I start with 99+ percent of the time: a Restek Premium 4mm single taper with wool (splitless injection), and a Restek Premium 4mm Precision split liner with wool (split injection).  Some simple bullet points explain my choices.

Restek Premium 4mm single taper with wool liner

• Best deactivated splitless liner and wool offered by Restek.
• Most appropriate liner ID for 0.25mm (and 0.32mm) ID GC columns.
• Wool at bottom aids sample homogenization and transfer to GC column.
• Wool at bottom is in cooler zone of Agilent inlet, helping to prevent compound thermal degradation.
• Wool at bottom traps non-volatile "dirt" that can compromise expensive GC column.
• Wool at bottom prevents sample from striking metal bottom seal, which can lead to compound degradation.
• Wool at bottom prevents less volatile compounds from striking metal bottom seal, where they have to travel up to GC column.
• Wool at bottom allows Concurrent Solvent Recondensation - Large Volume Splitless Injection.
• Wool can be blown out of the liner with dry, clean gas if analyzing very active compounds, including some pesticides.
• Single taper helps restrict sample contact with metal bottom seal.

Restek Premium 4mm Precision split liner with wool

• Best deactivated split liner and wool offered by Restek.
• Wool positioned to wipe syringe needle during injection, resulting in accurate split ratio and very repeatable injections.
• Wool helps mix/homogenize sample for very accurate and repeatable split injections.
• Open bottom on liner allows laminar flow of vaporized sample for accurate and repeatable split to bottom seal and GC column.

In addition to the high performance level for these liners, they also have low cost compared to more complex liner configurations.  There are good reasons to use different liners, but that's the subject for another post...