A facile method for simultaneous analysis of phytosterols, erythrodiol, uvaol, tocopherols and lutein in olive oils by LC-MS

Abstract

In this work a facile, sensitive and reliable method was developed and validated for simultaneous analysis of phytosterols, erythrodiol, uvaol, tocopherols and lutein in olive oils. Analytes extracted from saponified olive oils were directly determined by liquid chromatography-mass spectrometry (LC-MS) with atmospheric pressure chemical ionization (APCI). L-Ascorbic acid sodium salt was added into oils as an antioxidant prior to the saponification process, since tocopherols are sensitive to the effect of light and elevated temperature. We found that using L-ascorbic acid sodium salt made the sample treatment become a facile procedure. In this case we no longer need to use amber glass tubes or enwrap the tubes with aluminum foil. Separation was achieved on a C18 column with a gradient of acetonitrile/water (0.1% formic acid). Erythrodiol and uvaol were quantified separately for the first time in HPLC based analysis. The selected ion monitoring (SIM) mass spectra of 14 analytes were measured by using a mass spectrometer with an APCI ion source. Parameters including the linearity of the standard curves, the detection and quantification limits, recovery, repeatability and reproducibility were evaluated for the validation of the method.