Chromatography Forum

Hi-

I analyze neutral sugars as well as Glucuronic and galacturonic acids in environmental samples by High performance anion exchange chromatography with pulsed amperometric detection (DIONEX corp.).

One month ago I made a standard solution of all of these compounds and the chromatogram was impecable! Now the chromatogram of a standard (500 nM of e.a sugar) is ok for all sugars except the galacturonic acid which has a lower area (retention time at 11 min). His retention time did not shift but his surface is much smaller with an important tailing at the end. It is funny though but the glucuronic which is eluted after the galacturonic (retention time at 14 min) is totally OK.

I have prepared a fresh solution of galacturonic acid as well as fresh eluents but the problem persists. Do you think that there is a link with the efficiency of column ? (CarboPAC PA1)? How can chek this out ?

Thank you for your help

Christos

Since fresh standards and fresh mobile phase did not fix the problem, and since only one peak is affected, that leaves column chemistry as the only logical sources of the problem. The problem may simply be "junk" contaminating the column, and the fastest way to check is to simply replace the column. While you're at it, check with your column supplier to see if they have any recommendations for cleaning/regenerating the old column.

Thank you very much Tom. I suspected that something wrong went with the column and I followed a severe clean up procedure and now I am ok.

Christos

Greetings Christos,

I to do a lot of work on carbohydrates using a dionex PA1 and PAD. I have tried in the past to successfully resolve these two organic acids as well, with little success.

I was wondering if you would be willing to share your operating conditions (flow, eluent strength, temp, etc) I would be greatly appreciative. Thanks a bunch in advance.

K