Quantification of oleacein and oleuropein aglycone in olive oil using deuterated surrogates by normal‐phase ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry

An analytical method for the analysis of relevant secoiridoid‐based components in olive oil, oleacein and oleuropein aglycone, is described using for the first time deuterated surrogates. 0.2 g of sample was necessary to perform the analysis using liquid‐liquid extraction and ultrasound‐assisted extraction with a mixture of methanol/water (4:1, v/v). To avoid the formation of by‐products, normal‐phase ultra high performance liquid chromatography was chosen for the chromatographic separation. The selected mobile phase was a gradient mixture of tetrahydrofurane and hexane, and an ACE Excel 3 CN‐ES column as stationary phase. The detection and quantification was performed with a SYNAPT G2‐Si mass spectrometer. The calibration curves for oleacein and oleuropein aglycone were linear and quadratic, respectively. The validation was done at three levels of concentration. Relative errors from 0.1 to 10.5% and relative standard deviations lower than 9% were obtained. The method was applied to study different samples of olive oil.