Analytical determination of hydroxytyrosol in olive extract samples by micellar liquid chromatography

Hydroxytyrosol is a well-known natural phenolic component obtained from olive extract samples with antioxidant effects. A micellar liquid chromatography method to detect and quantify hydroxytyrosol in olive extract samples is described. Matrix resolution was performed using a Kromasil C18 column and a micellar mobile phase of sodium dodecyl sulphate (SDS) 0.05 M and 4% methanol buffered at pH 7. Detection was set by absorbance at 280 nm. Samples were diluted with 0.05 M SDS at pH 3 and directly injected, thus avoiding long tedious extractions. Hydroxytyrosol was eluted in 3.5 min without overlapping other matrix compounds. Validation was performed following the US FDA guideline. The main analytical parameters studied were: linearity (0.03–250 μg mL−1; r2 = 0.999), limit of detection and quantification (3 and 30 ng mL−1, respectively), intra- and inter-day precision (RSD, % <1.4 and <8.2, respectively), and robustness (RSD, % < 6.6). Recoveries were in the 88.5–98.9% range.