Chromatography Forum

Hi all
Im usin μBondapak CN Waters column for analysis of BenzCl and im askin you any tip for cleaning and regeneration of this type column.
Thnx in advance

That is an *old* column technology! Best to check with Waters for any specific recommendations, but in general do a reverse-flush with something that will solubilize whatever flavor of CRUD is on there.

CN columns are pretty tolerant of solvent- you can wash with organic solvent or water depending on what the "crud" dissolves in. You may need to go thought an intermediate solvent (like isopropanol) to go between normal phase solvents (like hexane) and water. Being silica based, you want to keep the pH below 7.5.

Im usin a combination of 1-hexane sulfonate sodium salt with ACN (55:45) for my analysis. The retention times of peaks are not stable and i have some problems with the cleaning and make the column usable again. I usually wash the column with water and store in ACN:H20 80:20. Can you give any advice for better results?
Thnx in advance

Let me elaborate on my earlier post. You have to make a judgement about what type of contamination (CRUD = Chromatographically Retained Undesirable Debris) is likely to be in your samples, and then flush the column with something which is a good solvent for that type of contamination. What you are doing sounds fine if the contaminants are salts, but would be totally inappropriate if you have fatty or non-polar CRUD (100% ACN or even ACN with some dichloromethane would be better in that case).

Thnx for the help, we will continue the procedure we follow, maybe we need to replace our method with a new one usin a C18 or usin a brand new CN column after an appropriate period

I just started using a Cn column and in the instructions it says to store in IPA.