Reverse phase high performance liquid chromatography”. Hydroxytyrosol and tyrosol are natural compounds of secoiridoid nature, derived from Olea Europaea L.
They are present in leaves, olives and other anatomic parts of olive, under different chemical structures, deriving from oleuropein and ligstroside, and are particularly interesting when they are present in extra virgin olive oil because they are related to health claim “to act as inhibitor of Ldl oxidative damage” as reported in Reg. Ue 432/2012 after an accurate European Safety Agency evaluation in the past years. Reference standards are missing for all the natural substances that contain these two aromatic alcohols, no analytical accurate and precise method to meet the health claim compliance was present among the reference methods of olive oil.
For the direct producers is important to report the claim on their bottle, because the quality of the product is an important commercial factor and only an international standardized method must be accepted for this purpose that take care of consumer health.
An international interest is present for this problem, in Eu and extra Eu countries.
The method was developed by Pierangela Rovellini and its team in Innovhub-Ssi srl. It was presented in Uni italian standardization body in 2016 and after a collaborative test of 10 italian laboratories was published as Uni:11702 standard in 2018.
It was presented in Iso and published as technical specification Ts 23942:2020. The Italian expert delegation of Uni agreed to transform it into a Is method, the same for international experts of other standardization bodies and in 2021 a new international collaborative study was performed.
The Iso Resolution 601/2021, stated that the collaborative study was approved at unanimity (18 approval), (0 against). 20 International laboratories participated in the experimental study, they were from 6 different countries: Italy, China, Germany, France, Turkey, Canada. Five different extra virgin olive oil samples were selected with different level content of these aromatic compounds.
The study was performed in the period march-may 2021, all the laboratories submitted their data, and it was a great success.
The data were evaluated, each sample was analyzed in duplicate and the results were treated in accordance with Iso 5725-1-2-5-6 statistical reference standard.
Hydroxytyrosol, tyrosol and their sum, showed optimum statistical precision parameters, seen also the high number of laboratories and the presence of laboratories that did this analysis for the first time. It meant that the method proposed is robust, well described and useful. The international study confirmed the italian study.
The Iso Resolution 614/21 of Iso/Tc34/Sc11 agreed that the amended method was ready to be submitted for the Dis ballot and transformed definitively in Is method.
An important teamwork is the base in providing the scientific community of new useful analytical methods.
Photo Olio Officina©