Overview
ISO 5132:2024 - "Animal and vegetable fats and oils - High-performance liquid chromatography (HPLC) analysis of phenolic antioxidants" - specifies a validated HPLC method for identifying and quantifying commonly used synthetic phenolic antioxidants in fats, oils and shortenings. The method covers sample extraction, chromatographic separation and calculation of concentrations for compounds normally added as antioxidants, including PG, OG, LG (dodecyl/lauryl gallate), THBP, TBHQ, NDGA, BHA (2‑ and 3‑isomers), BHT Alcohol (Ionox‑100) and BHT. Annex B provides a procedure to estimate the absence or maximum trace amount within analytical limits; Annex C addresses interference from canolol in rapeseed (canola) oil.
Key topics and requirements
- Scope: Quantification of specified synthetic phenolic antioxidants in animal and vegetable fats, oils and shortenings.
- Principle: Dilute sample in hexane, extract antioxidants into acetonitrile, dilute with isopropanol/acetonitrile (1:1) and analyse by reversed‑phase gradient HPLC with UV detection at 280 nm.
- Reagents & solvents: HPLC‑grade acetonitrile, 2‑propanol, hexane (or isohexane), high‑purity water, acetic acid; saturated hexane/acetonitrile extraction solvents are recommended.
- Apparatus: Gradient HPLC system with UV/PDA detector, C18 reversed‑phase column (several column dimension options provided), nitrogen blow‑down evaporator or rotary evaporator, volumetric glassware and analytical balance.
- Chromatographic conditions (summary): Column temp 40 °C; typical gradient from 30% to 100% eluent B (acetonitrile + 5% acetic acid) over 10 min, hold 4 min; injection ~5 µl (adjust per column); data collection 0–14 min.
- Sample prep highlights: ~4 g sample; triple extraction with acetonitrile saturated with hexane; evaporate to 3–4 ml (do not dry); reconstitute to 10 ml with acetonitrile/2‑propanol; TBHQ/BHT/BHA samples should be analysed within 4 hours.
- Performance & validation: Expected recoveries: ~90–95% for TBHQ/BHT/BHA and ~98% for propyl/octyl/lauryl gallates. A multi‑laboratory collaborative validation study is reported in Annex A.
- Calculations: Concentrations expressed in mg/kg using peak area ratios and recovery correction (formula provided in the standard).
Applications and users
ISO 5132:2024 is intended for:
- Quality control and regulatory compliance testing in edible oil manufacturing and refining
- Food safety and market surveillance laboratories monitoring antioxidant residues
- Research and development labs studying antioxidant stability and migration
- Accreditation bodies and standardization organizations adopting harmonized HPLC methods
Keywords for practical search: ISO 5132:2024, HPLC analysis, phenolic antioxidants, TBHQ, BHT, BHA, propyl gallate, lauryl gallate, oil testing, canolol interference.
Related standards
- The method represents adoption of AOCS Official Method Ce 6a‑2021 (HPLC analysis of phenolic antioxidants).
- Developed by ISO/TC 34/SC 11 (Animal and vegetable fats and oils).