Optimization and validation of a rapid liquid chromatography method for determination of the main polyphenolic compounds in table olives and in olive paste

- Ultrasound-assisted extraction variables, such as composition, time and olive stone were optimized.
- The intraday precision values of real samples ranged from 1.12% to 7.64%.
- Recovery values ranged from 90.0% to 109.1%, for most analytes.
- Individual polyphenols were quantified in Arbequina and Carrasqueña olive samples.

A high performance liquid chromatography method, coupled to diode-array and fluorescence detectors, with a previous solid-liquid extraction, has been developed for the simultaneous detection and quantification of polyphenolic compounds in table olives and in olive paste. The effects of extraction variables have been studied by response surface methodology. The best conditions were extraction with 100% methanol (2 mM NaF) during 30 min for table olives, and 91% methanol (2 mM NaF) during 40 min for olive paste. Chromatographic separation of 26 polyphenols from different families was optimized. This method provides high linearity, in all cases higher than 98.65%, and high sensitivity whose detection limits ranged between 0.08 and 1.11 μg/mL. The validated method has been applied for the determination of polyphenols in table olive and olive paste samples. The intra-day and inter-day assay repeatability, in the analysis of real samples was less than 7.6 and 11%, respectively.