An analytical method for the simultaneous determination of hydroxytyrosol and tyrosol in differenttypes
of olive extract raw materials and cosmetic cream samples has been developed. The determination was
performed by liquid chromatography with UV spectrophotometric detection. Different chromatographic
parameters, such as mobile phase pH and composition, oven temperature and different sample preparation
variables were studied. The best chromatographic separation was obtained under the following
conditions: C18 column set at 35 ◦C and isocratic elution of a mixture ethanol: 1% acetic acid solution
at pH 5 (5:95, v/v) as mobile phase pumped at 1 mL min−1. The detection wavelength was set at 280 nm
and the total run time required for the chromatographic analysis was 10 min, except for cosmetic cream
samples where 20 min runtime was required (including a cleaning step). The method was satisfactorily
applied to 23 samples including solid, water-soluble and fat-soluble olive extracts and cosmetic cream
samples containing hydroxytyrosol and tyrosol. Good recoveries (95–107%) and repeatability (1.1–3.6%)
were obtained, besides of limits of detection values below the g mL−1 level. These good analytical features,
as well as its environmentally-friendly characteristics, make the presented method suitable to carry
out both the control of the whole manufacture process of raw materials containing the target analytes
and the quality control of the finished cosmetic products.