Development of a LC-MS/MS method for urinary hydroxytyrosol as a marker for consumption of olive oil

The aim of this study was to develop and validate a LC-MS/MS method to quantitate hydroxytyrosol in urine for clinical studies to monitor compliance of consumption of dietary extra virgin olive oil. Both pre-analytical and analytical issues were examined. The stability of hydroxytyrosol was monitored in both urine and synthetic urine at four different temperatures (room temperature, 4 °C, −20 °C, or −80 °C) for four weeks either with or without the additive acetic acid. The LC-MS/MS method was validated by performing linearity, imprecision, recovery, and carryover studies.