Identification and quantification of isomers of secoiridoids and flavonoids in olive oil by using a capillary zone electrophoresis method

Separation and determination of individual phenolic compounds in the extracts obtained from olive oil by liquid-liquid extraction (LLE) or solid phase extraction (SPE) use high-performance liquid chromatography (HPLC) analysis coupled mostly with UV detection, although electrochemical, fluorescence and mass spectrometry detection systems have also been proposed. Gas chromatography analysis is less common because the derivatization step is essential. Nowadays, there is increasing interest in CE due to the high separation efficiency which can be obtained, the short analysis times that can result, the relatively low cost of the instrumentation and the suitability of CE for many types of compounds. In particular, this technique has recently been used for the analysis of phenolic compounds of extravirgin olive oil, olive mill wastewater and alperujo. In spite of the effort of several research groups to develop rapid and reliable CE methods for the analysis of the complete polyphenolic fraction of virgin olive oil, there are two important families, present in this polar fraction, which are not well characterized by CE: secoiridoids and flavonoids.