Nano and rapid resolution liquid chromatography-electrospray ionization-time of flight mass spectrometry to identify and quantify phenolic compounds in olive oil.

The applicability of nanoLC-ESI-TOF MS for the analysis of phenolic compounds in olive oil was studied and compared with a HPLC method. After the injection, the compounds were focused on a short capillary trapping column (100 microm id, effective length 20 mm, 5 microm particle size) and then nanoLC analysis was carried out in a fused silica capillary column (75 microm id, effective length 10 microm, 3 microm particle size) packed with C18 stationary phase. The mobile phase was a mixture of water + 0.5% acetic acid and ACN eluting at 300 nL/min in a gradient mode. Phenolic compounds from different families were identified and quantified. The quality parameters of the nanoLC method (linearity, LODs and LOQs, repeatability) were evaluated and compared with those obtained with HPLC. The new methodology presents better sensitivity (reaching LOD values below 1 ppb) with less consumption of mobile phases, but worse repeatability, especially inter-day repeatability, resulting in more difficulties to get highly accurate quantification. The results described in this article open up the application fields of this technique to cover a larger variety of compounds and its advantages will make it especially useful for the analysis of samples containing low concentration of phenolic compounds, as for instance, in biological samples.