Chromatography Forum

hi!

Currently i'm using 2.0 mm ID Baffled Inlet Liners for the analysis of PAH.
After a while they get useless.
Is there a way to clean them in an efficient way?
or is this not beneficial because you can create active sites...

Best regards,

Willem

What's your meaning of "After a while they get useless" ?
Active sites are crated after you wash the liner with acid or base solution which destroyed the Si-O bonding of deactivated silanol groups. You can use organic solvent (acetonic, acetone, methanol) preferably using ultrasonic bath ( if the liner has no fritted glass) for efficient cleaning of liner.

well after a while we get increased responses for the reinjection of standards.
also the internal standards aren't stable over time...
they increase or decrease after running around 70 samples.

using a new liner ussally solves these problems.

A baffled liner is likely difficult to clean well. Possible putting them in a muffle furnace after sonication will ensure they are clean, but they would need to be treated with a silanization product like DMDCS (the muffling in particular can drive metal ions out to the surface). This works for some applications, but not as well as a new one, if only because using a new one reduces speculation on the liner as a trouble source.

You answered your own question. It's best to just use new liners. The time and effort expended to clean a liner may not be cost effective.

I'll drip solvent through my liners to clean them out, usually water, methanol, acetone, and isopentane if that doesn't help I pitch them.

I've cleaned some liners successfully. I used NoChromix to clean them then rinsed with methanol and toluene, followed by deactivation with DMDCS (5% in toluene). If you have lots of them to clean it may make sense but to do just a couple at a time is likely not cost effective. I'm a grad student so I have more time than money...

I think we have used just about all of these methods. Depending on how dirty they are they will clean up nicely or not at all. Muffle furnace works well, as does solvent cleaning for organic deposits like tars and char. We can do batches of 10 or more at a time so it can pay off if you have the time to do it.

Cleaning them for use in PCB or PAH analysis should be fairly easy, cleaning them for pesticide work where you can get a lot of break down is more demanding.

When I was running 8270 Semivolatiles analysis I was in the habit of changing liners every morning before starting the next 24 hours of samples, which was usually 20-30 samples in a run. Change liner and clip about 3-4 inches of column each morning usually did the trick without needing to recalibrate each time.