Solid Phase Extraction for the Direct Extraction of Phospholipids in Virgin Olive Oil and their Determination by Hydrophilic Interaction Liquid Chromatography Coupled to Mass Spectrometry

Phospholipids (PLs) are the most important class of polar lipids in foods because they are the major components of cell membranes in animal and plant tissues. Recent studies have shown that PLs can have a positive nutritional effect on human health, such as reducing the risk of cardiovascular disease, reducing blood cholesterol levels and enhancing brain function [ ]. As an integral component of cell membranes, they are involved in cell signalling and, therefore, they are indispensable for the communication and interaction between body cells [ - ]. Although some influences of phospholipids on health are controversial, overall dietary phospholipids are most likely to have a positive effect on health [ ]. Nevertheless, phospholipids are poorly investigated as minor compounds in olive oil and in literature the phospholipids extraction has been essentially developed by liquid-liquid extraction (LLE). The aim of this work was to compare the effectiveness of a previous LLE extraction method with a direct separation and purification of olive oil phospholipids with two different SPE sorbents (silica and diol). As far we are concerned this is the first application of SPE for the direct extraction of phospholipids in virgin olive oil. Furthermore, the extracts were analyzed by HPLC-ESI-qTOF-MS to obtain basic information useful for a possible identification of the single components. To this aim, a new separation method was established using an hydrophilic fused core liquid chromatography column (HILIC). The HILIC chromatography is readily compatible with electrospray ionization and results in higher sensitivity and improved peak shapes. The SPE diol extraction and HPLC-ESI-TOF-MS methodology have demonstrated to be very useful to determine the phospholipids in not filtered virgin olive oil and also in a veiled virgin olive oil subjected to a glyceridic crystallization due to a temperature decrease. In fact, it could be observed that crystallization caused a significant decrease in the phospholipids fraction.