Dear Christoph, in former years, we separated Tyr, Phe, Trp by standard RP18, and acidic amino acids could be separated by anion exchange chromatography using Nucleosil SB. For the other ones, there is no "perfect" procedure to my knowledge. For OPA-amino acids, there are severals columns e.g. RP18, Hypersil ODS etc. useful, but we never did.
I am currently using a Phenyl-hexyl for OPA amino acid separation and that works really well. For underivatised I have used HILIC in the past, it works but is tricky to get right.