Chromatography Forum

Hi everyone.

I've been wondering about how to best clean a C18 LC-column and thought I'd like to hear what you think about the way I'm used to do.

Generally, cleaning instruction as I'm used to say to clean column using mobile phase were buffer (if used) is replaced with water then go to 100 % organic and then store it in 100 % organic. Most of the time when I wasn't as used to cleaning procedures, I just cleaned column with low organic, then changed mobile phase and then flushed the column with 100 % organic for storage.
However, ever since I had major issues with columns being dirty, I started using a gradient going from 10-100 % organic with great results. Ever since, I've used this method for cleaning columns and haven't had the same problems as before. I always think this way gives better possibilities to rinse the column of a broader range of impurities/dirt.

What do you think is the best way to clean a column? Is anyone else doing as I'm doing? Is this procedure a good way to keep the columns in good shape?

Regards
/Pär

The general "trick" is to flush the column with something that will solubilize the bound junk while avoiding precipitation and immiscibility issues. High organic is not always the best approach (if you have precipitated salts, for example).

Bottom line, if the gradient is working for you, it's fine.

First of all please use the column maintenance instructions from the manufacturer of your column. Than talk to their tech support, let them know what kind of junk is in your sample. To increase lifetime of a column a good sample preparation, for example with SPE, or filtration, is highly recommended. You will find a lot of protocols on the websites of the SPE manufacturers like UTC, Waters, Agilent (Varian), Phenomenex etc.!
When I worked in pharmaceutical R&D and had to analyse something like a creme I used one step which might be a little bit unusual. I flushed the column with "hot" water.
All cleaning procedures will help you to overcome the time a new column needs to be delivered to your lab.........
Good luck.

Hi Perrman,

The procedure you describe is nearly perfect. I’ve been doing the same thing for many years and never experienced trouble with it. It allows you to exchange buffer containing mobile phases with the final 100 % organic without risking precipitation. And then it's kind of automated so you don't have to stay with your system and service it while the process is running. The trick here is to apply the optimal gradient slope so that you don’t shift from aqueous to organic too rapidly.

Best Regards