Column wash

Record: 888

Category: Column Problem
Product:
Sample:

Question
I’ll try that next week! Thanks!

Please permit me to ask a stupid question regarding washing the column with water: if the noise is caused by water, would a water wash remove active sites or something? I’d like to understand better why they think this might work.

Also, I’m wondering that if the noise is caused by water, if running with a greater ratio of acetonitrile:water would be helpful in general? Say 95%ACN instead of 90%, or even 100% ACN? I do have some leeway with the method as far as mobile phase goes, as long as my chromatography is good.

Thanks so much for your continued assistance!

Answer
The water wash should not remove active sites; it should only remove the compounds that are causing the noise. The technical support has not given much information into the why, but I may be able to speculate.

Our production site has changed the shipping solvent from 75% acetonitrile in water to 100% acetonitrile. During production they use many column volumes of solvent to pack the columns, perhaps the use of water in the past helped wash off whatever is causing the noise. Now the preparation does not use water so more of those compounds remain present.

You may try to run in a higher concentration of ACN. It may reduce the noise issue; however I’d really like to get to the bottom of the problem.

My product manager would like to know if you have checked/cleaned your detector. I think he would like to eliminate the possibility that the sensitive detector may be picking up impurities in the cell.

Thank you for your continued patience!

 
 
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