3M Empore XDB-XC Filters vs Quality of Acetonitrile

[Yorkie31]

Has anyone had any experience with the 3M Empore XDB-XC filters.

I had previously being experiencing problems with ghost peaks during a gradient elution, using ammonium acetate and acetonitrile (Hopefully see link below)

http://www.sepsci.com/chromforum/viewto ... highlight=

During these discussions it was suggested that I look at the above filters from an LC-GC America article. The filters seemed to work erratically. Sometimes giving good results, and sometimes really not doing anything.

Just by pure chance, a different supplier of acteonitrile was used. This appeared to give a far cleaner gradient.

Originally we had been using BDH HPLC Grade (Far UV). We then tried Riedal-De-Haen/Sigma CHROMASOLV Plus.

I wondered if anyone else had done any work with either the above mentioned filters? or changing acetonitrile.

It seems to me, that although the filters have some effect on cleaning up the gradient by removing any unwanted organics from water, buffer etc, the actual acetonitrile plays a bigger role than first thought.

Any thoughts?
Cheers
Anthony

[Yorkie31]

Further to the above, see the link below for a discussion on acetonitrile used in gradient analysis:

http://www.sepsci.com/chromforum/viewtopic.php?t=4409

I would be quite interested to see what came out of this?

Cheers
Anthony

[Bruce Hamilton]

Just by pure chance, a different supplier of acteonitrile was used. This appeared to give a far cleaner gradient.

Originally we had been using BDH HPLC Grade (Far UV). We then tried Riedal-De-Haen/Sigma CHROMASOLV Plus.

I wondered if anyone else had done any work with either the above mentioned filters? or changing acetonitrile.

It seems to me, that although the filters have some effect on cleaning up the gradient by removing any unwanted organics from water, buffer etc, the actual acetonitrile plays a bigger role than first thought.

Besides the annoyance factor, one problem with ghosts is that they come in all genders, colours and creeds. It's a really good idea to have at least two approved suppliers of any common HPLC solvent. Being able to swap supplier products helps when investigating problems. I would prefer to try and purchase better quality solvent than to add a purification step.

I suspect you have a intermittent source of the ghosts arising from your solvent cleanup or sample and mobile phase preparation. You may need to be systematic to confirm whether the Empore disk process can be made consistent ( flowrate, solvent volume, etc ). If it's not consistent, it's no benefit.

Bruce Hamilton