mostly water/minimal retention

[sepscientologist]

Does anyone recall a good analyte that has some but not lot's of retention (say k' of 2 to 5) in something like 95% water with a garden variety C18 column or embedded polar C18?

[Gerhard Kratz]

I would try coffein, just inject black coffee without sugar and milk. Good luck.

[mckrause]

Propamocarb comes flying off of C18, and if you are using MS as your detector it is very sensitive. It will be slightly retained on a more polar phase.