Extraction with 100 % methanol with rotary mixing gave greater recovery than with 50% methanol (Supplemental figure ). Regardless of the volume used, only 85% of added oleuropein was recovered Validation results for the HPLC-FLD method are presented in Table ; those for UPLC-MS and UPLC-UV methods are presented in supplemental Tables and, respectively. In the interest of clarity, only back-calculated concentrations are presented rather than detector responses.