Impurity profiling of penicillin on an ARION® Plus C18, 5.0 µm column (250 mm × 4.6 mm, ARI-5720-LM46). Proprietary gradient elution at 1.2 ml/min with UV detection at 254 nm. The application compares the ARION® column with a competitive column (Competitor LI): the ARION® separation resolves the individual impurity peaks over the whole 30-minute run, while on the competitive column several of them remain unresolved.