YMC-ODS-AQ columns

[Tata Venkata]

Hello all,

Hello all,
I have an strange column issue. About 3-4 years ago, I developed a method using a YMC-ODS-AQ column (100% aqueous w/ion pair, pH 3.0, isocratic conditions. I cannot use any organic because of the polar nature of analytes). The columns were then made in Japan and sold in US through Waters. A few months ago I purchased the YMC-ODS-AQ columns form Waters. I cannot obtain stable peak RT, (yes I equilibrated the columns exhaustively with the ion pair agent almost 500 column volumes). Then I realized these columns are now packed in US and Ireland. This change has definitely affected the column performance. Waters cannot provide any columns made in Japan or maybe they are not even packed in Japan any more. I went back and fished out my old Japanese columns and they work fine. All 4 lots of them. But I am concerned about transferring a method knowing what I know. Then I tried Phenomenex Synergi Hydro RP columns (considered equivalent to YMC- AQ). Same problems (peak shifting etc). Any thoughts on this issue? Anyone have any ideas for reliable alternates for YMC-ODS-AQ?

Thnaks in advance for any suggestions.

VRT

[Bryan Evans]

Hi Tata,

If you would be so kind - please get in tough with me
(via email or phone) and I will gladly provide you with an alternative
column (Unison UK C18). Thank you very much.

[Uwe Neue]

Unstable retention times? I'll be glad to troubleshoot the problem with you, but I need much more information about your mobile phase. If you do not want to give the details in public, you can contact me at one of the e-mail addresses below.

Uwe Neue
Waters Corporation

uwe_neue@waters.com
uwe.neue@prodigy.net