A rapid and simple method for the analysis of bioactive compounds in olive oil refining by-products by liquid chromatography with ultraviolet and mass spectrometry detection

In this study, a simple and rapid reversed phase high performance liquid chromatography with ultraviolet detection (HPLC-UV) method was developed and validated for the simultaneous analysis of erythrodiol, tocopherols, phytosterols and squalene in olive oil and olive pomace oil chemical and physical refining by-products. A sample pretreatment without saponification, solely based on n-hexane extraction, allowed direct analysis of the target compounds from the by-product samples. α-tocopherol, β-sitosterol and squalene were quantified by external calibration. The highest concentrations of these compounds were found in olive oil chemical refining by products (i.e. 0.19%, 4.1% and 19.1% m/m, respectively). Afterwards, the method was adapted to high performance liquid chromatography with electrospray ionisation mass spectrometry detection (HPLC-MS). Positive ESI (+ESI) allowed better sensitivity than negative ESI (−ESI), and detection of all the target compounds except squalene. In addition to α-tocopherol and β-sitosterol, the presence of erythrodiol in the complex by-product samples could be confirmed due to the excellent selectivity of MS detection.