ISO 23942:2022

Overview - ISO 23942:2022 (RP‑HPLC method for olive oil phenolics)

ISO 23942:2022 specifies a validated analytical procedure for the quantitative determination of hydroxytyrosol and tyrosol in extra virgin olive oil (and other commercial olive oil categories) using reverse phase high performance liquid chromatography (RP‑HPLC) with spectrophotometric detection (280 nm). The method covers sample extraction, hydrolysis, chromatographic separation, identification, calculation of results and precision requirements.

Key topics and technical requirements

• Principle: Extract biophenolic fraction with methanol/water, hydrolyse esterified forms to free hydroxytyrosol and tyrosol, separate and quantify by RP‑HPLC at 280 nm using external standards.
• Sample preparation: Typical procedure uses 2 g oil + 5 ml methanol/water (80/20 v/v), vortex, ultrasonic extraction (15 min), centrifugation (5 000 r/min, 25 min), filtration, evaporation and hydrolysis with ethanol/water/sulphuric acid (50/40/10 v/v/v) at 40 °C for 1 h followed by overnight cooling.
• Chromatography: RP‑18 column example (4.6 mm × 25 cm, 5 µm), ternary solvents (A = water + 0.2 % H3PO4, B = methanol, C = acetonitrile), programmed gradient, flow 1.0 ml/min, injection volume 20 µl. External standard solution of hydroxytyrosol and tyrosol (final 50 mg/L) is used for identification and quantification.
• Detection & identification: UV/spectrophotometric detection at 280 nm; retention-time matching with external standards (hydroxytyrosol elutes before tyrosol). Photodiode array (PDA) can assist spectral confirmation.
• Results & calculation: Peak areas converted to mg/kg using provided formulae and a multiplication factor (250) that accounts for extraction and injection volumes.
• Quality and validation: Precision (repeatability and reproducibility) and method validation data are addressed (see Sections 10 and Annex C). Limits of detection and quantification are given in Annex B.
• Reagents & apparatus: Lists chromatographic-grade solvents, reference standards and typical HPLC system components. Specific column examples are informative only, not endorsements.

Applications and users

• Who uses it: Official food control laboratories, olive oil producers, certification bodies, research labs and quality assurance teams.
• Practical uses:
  • Verify phenolic content for quality classification and health‑related labeling.
  • Support product authentication and compositional analysis.
  • Provide reproducible data for regulatory compliance, R&D and comparative studies of olive oil varieties and processing.

Related standards and notes

• Sampling recommendations reference ISO 5555 for representative oil sampling.
• This first edition replaces ISO/TS 23942:2020 and includes additional validation studies (Annex C).
• See Annex A (chromatogram example), Annex B (LOD/LOQ) and Annex C (validation studies) for implementation details.

Keywords: ISO 23942:2022, hydroxytyrosol, tyrosol, extra virgin olive oil, RP‑HPLC, reverse phase HPLC, spectrophotometric detection, olive oil phenolics, analytical method, method validation.