We initially employed HPLC grade methanol but switched to HPLC acetonitrile because of known issues with psilocybin peak shape . Additionally, acetonitrile offers reduced solvent background absorption for low-wavelength quantitation, enhanced elution capacity, and reduced operating pressures compared to methanol . The organic phase ramp was programmed to switch to the organic phase near the retention time at which psilocybin elutes. By using this approach, psilocybin and psilocin elute efficiently.