Ten packed standard columns were evaluated for the separation of the sixteen US Environmental Protection Agency polycyclic aromatic hydrocarbons (PAHs) by gradient HPLC. This was done in a systematic way by the use of chemometric parameters such as window diagrams and chromatographic response factors and a computer program to calculate k′, α, N and R s. New approaches to a more economical and ecological use of HPLC solvents were evaluated. Good results were achieved by recycling acetonitrile-water waste by distillation as the azeotrope and using it again with methanol in an HPLC system. Supercritical fluid chromatography with carbon dioxide as supercritical fluid and acetonitrile as modifier was compared with HPLC, using the same column in both methods, for the determination of PAHs.