SB806M-HQ column

Record: 390

Category: Column Problem
Product: SB
Sample:

Question
Thank you for your help. Below is the RI signal of our polymer, not the largest but pretty big at ~450 KD. Do you have any explanation why the one-year old column has a little bit longer retention time compared to a brand new column?

We are running one column at 1.0 ml/Min flow. The mobile phase is 1x PBS at pH 7.5.

What would you recommend? We are using MALS so a “ linear column” is not necessary. We would like to resolve MW up to 1 million.

Answer
Regarding the result difference observed by the new and old columns (I believe both are SB-806M HQ and the old one is not SB-806 HQ, is this correct?), there could be two types of possibilities for this difference.

-One is due to gel-to-gel lot differences of the column. Do you have certificate of analysis from both columns? You may compare their original analytical performances.

-Other can be due to the change in column over the year.
Do you have chromatograms that were collected 1 year ago with the old column? Have you noticed any change in retention time over the time?
Also do you observe any back-pressure differences in two columns and/or when the column was new?
There could be a possibility that sample/solvent had been adsorbed on the gel surface and making the retention time longer. Although both chromatograms show nice symmetrical peaks and straight calibration curves. So I would not think this is any critical problem. Do you perform any cleaning steps over a time? Another point to note is that although it is highly dependent on how you use the column, but generally the column life of polymer-based column is about 1 year or so.

Would you be able to share a chromatogram that shows the separation of 150KDa and 450KDa compounds using SB-806M HQ?
I would like to see it to consider if any of other column can provide a better separation.

 
 
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