Chromatography Forum

Hi All


I'm an using a UPLC column and after about 1500 injections I noticed that the tailing of my peaks started to increase and as a result my column efficiency decreased. The column efficiency started off at about 6000 for my active and then reduced to about 2500. I reversed the column and made 1 injection and the effieciency increased to the expected efficiency of about 6000. It seems that there might be a blockage at the inlet of my column. Does anyone know if the inlet and oulet frits are the same size? If the frits are the same size, then I'm thinking of reversing my column and using it in this direction. Has anyone tried this yet? Any comments would be appreciated.
Thanks
Michael Carolus

If you have a Waters Acquity column, you can reverse the column, or change the inlet frit as this is the same as the one in your inline filter just before the column.

Ace

Thanks Ace. I'm using a Waters Acquity column. I'll reverse the column and hopefully I can extend the column life for a while longer.
thanks again

Hi,
Don't know if you already reversed your Acquity column but i don't think this would be a good idea. To my knowledge, this kind of column cannot be returned because the inlet frit has a higher porosity than the outlet frit. Thus, there is a high risk of sorbent leakage when reversing column. Refer to the column manual contained in the eCord.

Regards,

Hi,
Don't know if you already reversed your Acquity column but i don't think this would be a good idea. To my knowledge, this kind of column cannot be returned because the inlet frit has a higher porosity than the outlet frit. Thus, there is a high risk of sorbent leakage when reversing column. Refer to the column manual contained in the eCord.

Regards,

I was always thinking that this was in the very beginning of the Acquity columns, but that they are using now the same frits inlet and outlet

Ace

Hi All

Thanks for the comments. I managed to get confirmation from Waters about the frit sizes - "At this point in time, the inlet and outlet frits of the column are the same, and the column can be reversed."
Thanks again
Michael

OK thanks for the confirmation. As you said Aceto_81, the different frit size was an information we get when we started working with UPLC a few years ago now. The column reversibility is a new option we will use.

Thanks to all.

I think you should be happy that you got 1500 injections from a UPLC column. That is pretty good even for a standard column.

Another thing to remember: since the UPLC columns are packed with smaller particles, they have end frits with smaller pore sizes. This means that they are more susceptible to plugging by particulates. Filtering is even more important, and 0.45 um is probably not good enough. Filter through 0.2 or even 0.1 um.