Chromatography Forum

A quick question on best practice with regards to column washing. When running a mobile phase of 80:20 water:ACN with 0.1% phosphoric acid (isocratic runs), would you suggest a daily column wash? At the moment we are running this every day without any kind of wash procedures, and I'm wondering if this is bad practice?

Many thanks.

Column wash after one day is always not bad. Just to get off matrix from your samples and get ready for the next day. I would wash with 80:20 ACN: water and than go back to your mobile phase.

If you are running this every day without washing procedure, there is only a question of time before your column will be affected by the junk in the samples (depending on how clean your sample is of course).
I would recommend adding a column wash as a last injection in you run sequence, it is an easy way of getting it done.
Try setting it up as Gerhard recommended, or perhaps make a gradient from 20/80 ACN/H2O to 80/20 ACN/H2O.

See above. Do the wash automatically at the end of the sequence, or manually.

If one doesn't know, just do the wash after morning routine purge of pump, then just give enough time to re-equilibrate once you return to your analysis conditions.

Great, many thanks for the responses! I will take your advice and begin doing this.