Chromatography Forum

Hi,
I am getting tailing on an early non-polar compound. I don't have tailing on later eluting polar compounds and their retention times are not shorter over time. My question is - if the column is degrading do non-polar compounds start to tail ? The column is about a year installed and is used every day so is due for replacement but I don't want to if not necessary. The column is CPWax52CB. Any help gratefully received.
WK

When did you last do inlet maintenance ?

Peter

Hi

Could you post some more details and a chromatogram?

There is a post box near Mornington Crescent

Regards

Ralph

You could add "The Infinite Monkey Cage" to your BBC Radio 4 list

Hi,
Thanks for the replies.
I will try to get time to do some proper logical inlet maintenance.
I suspect the pre-packed wool liners we buy in are not always tightly packed enough. I will try to shove some more wool into one and try that (PE PSS injector - 2mm id liner).
Regards
WK

(I will add The Infinite Monkey Cage. Been listening to Rich Hall's US Election show).

If you have tailing only of the non-polar component then the most likely culprit is a fragment of septum in the inlet liner. I would be very surprised if packing in more wool would improve anything.

Details on conditions would help.

Peter

Hi Peter,
I packed the liner with more wool. I swabbed the inlet with methanol. I also cleaned the septum nut hole out and removed septum material in the process.
I checked the column insertion distance in the inlet. One at a time and nothing improved. So I replaced the column and the non-polar component no longer tails.
Using a CPwax52CB it would appear that the peak shape has deteriorated - but the retention times appear to be similar over time. I suppose that is a good thing !
By the way - I have re-installed the liner out of the box - with relatively loose wool.
Thanks for the help
Regards WK

Hi WK

I apologise for deviating from the post

but yes

Rich Hall's US Election show is so good - did you hear the post election one?
Call 555 0101


Ralph

https://en.wikipedia.org/wiki/Rich_Hall

Hi WK

Thanks for the feedback. Both septum fragments and a deteriorated column can cause non-polar compounds to tail, so if the tailing comes back do the cheap inlet check before you change the expensive column.

Peter