HPLC analysis of olive oil

HPLC analysis is one of the most important tools for documenting polyphenols in olive oil. It provides a measurement in mg/kg and makes it possible to link a specific number to a specific batch.

For a premium oil, simply saying "high polyphenol content" is not enough. The value needs to be traceable to a sample, a method, and a laboratory.

What is HPLC?

HPLC stands for High-Performance Liquid Chromatography. It is a laboratory method that separates, identifies, and quantifies chemical compounds in a sample.

In olive oil, HPLC is used to analyze various phenolic compounds and their derivatives. These can include hydroxytyrosol, tyrosol, oleocanthal, oleuropein, and other substances that together form the oil's polyphenol profile.

The method is not a sensory panel and not a health test. It is a chemical analysis.

How an HPLC analysis is performed

An oil sample is mixed with solvents to extract the polyphenols from the fat. The extract is then injected into an HPLC instrument, where the compounds are separated and measured.

Simply put, the analysis consists of three parts:

The column. The sample passes through a column filled with a material that causes different compounds to move through the system at different speeds.

The solvent flow. A controlled mixture of solvents drives the sample through the column with high precision.

The detector. When a compound passes the detector, a signal is registered. The strength of the signal is used to calculate the amount of the substance.

The result is a chromatogram: a graph with peaks corresponding to different compounds. The peaks are compared with reference substances and used to calculate the concentration.

What an mg/kg value actually represents

The result is often expressed in milligrams per kilogram of oil, mg/kg. It describes how much of the analyzed phenolic compounds are present in the sample at the time of analysis.

A value like 1,004 mg/kg is therefore not a feeling, an index, or an estimate. It is a measured quantity in a specific sample, analyzed with a specified method at a specified laboratory.

Vala Selection's reference batch 2025-VL-MIR-001 was analyzed at the University of Split and measured at 1,004 mg/kg. This figure describes the analyzed batch, not a general promise that every future harvest will have the exact same value.

Why HPLC values can differ between laboratories

Even when two laboratories use HPLC, the results can differ. This does not automatically mean that an analysis is wrong. It means that the method needs to be understood.

Some common differences are:

• Extraction method. Different solvents and procedures capture polyphenols with varying efficiency.
• Column and solvent flow. Separation affects which substances are clearly identified.
• Calibration. Quantification is based on reference substances and calibration.
• Which compounds are included. A broader or narrower selection affects the total sum.

This is why serious communication about polyphenol content should specify the batch, method, and laboratory. A number without context is weaker than a number that can be traced.

What HPLC does not measure

HPLC measures chemical composition. It does not measure how the oil tastes, how long it lasts in your kitchen, or its biological effect in the body.

This means that the HPLC number should be used precisely. It can confirm that a batch contains a certain amount of analyzed polyphenols. It should not be used as a standalone medical claim.

The EU-approved health claim for olive oil polyphenols concerns the protection of blood lipids from oxidative stress and is linked to a threshold value per 20 g of olive oil. Read more on the page about polyphenols and oxidative stress.

Why HPLC is important for Vala Selection

Vala Selection works with small batches, clear origin, and documented polyphenol content. HPLC analysis is part of that transparency.

It helps us to:

• link polyphenol content to a specific batch
• monitor variation between harvest years
• communicate quality without exaggerated health promises
• show the difference between regular olive oil, premium oil, and high-polyphenol olive oil

This is also why we are careful about how numbers are presented. A high value is relevant only when it is traceable.

More information

About polyphenols as a group: polyphenols in olive oil.

About the EFSA claim and threshold requirement: polyphenols and oxidative stress.

About individual compounds: oleocanthal and oleuropein.

Sources: HPLC analysis performed at the University of Split. IOC Trade Standard COI/T.15/NC No 3/Rev. 16. Batch 2025-VL-MIR-001.