Chromatography Forum

I’m looking for the recipe of a really good cleaning mixture for HPLC. The recipe was given by a Dionex engineer to me.

I can remember that following chemicals were included:
Water
Methanol
Acetonitrile
Isopropanol
Formic acid or Acetic acid

Unfortunately, I can’t remember the proper amount for each chemical.

Any help will be appreciated.

It is my opinion that you may have been given some bad advice. Please do not use a "universal" cleaning solution for the flow path of your HPLC (I sure hope you are not asking for a solution to clean your column.... and I hope you have already bypassed the column with a zero dead volume union and restrictor). So called universal washing solutions are a compromise at best, used when the person advising you has no idea what you are doing or have been doing. Instead, they should ask for more details, just like any experienced person would before giving advice. The BEST cleaning solution to wash your HPLC flow path with is the one that will fully (fully = 100%) dissolve the material that you are trying to rinse from it. What sample(s) are you trying to rinse? Use a single solvent that the sample will be fully dissolved in AND that is same for use in your HPLC system (safe for use with the tubing, seals, fittings, degasser chamber(s), flow cell and flow path of YOUR HPLC system). If any buffers have been used with the system, then start with a pure water rinse (or optionally add some acid to the water, such as 1% formic, would be fine and is not too strong).

If you have partially or fully plugged the system, then first do some trouble shooting to find the clog or obstruction, then repair it first.

Perhaps most importantly of all, get some professional help from an experienced liquid chromatographer to do it all right and not damage the system.

they say in equal amounts, but acids are not mentioned (page 21), then page 31 - 0.2% FA:

https://www.waters.com/webassets/cms/li ... Tricks.pdf

I recall I have seen the same proportions somewhere in Dionex manuals.