SIST EN ISO 13884:2005

Overview

EN ISO 13884:2005 (identical to ISO 13884:2003) specifies an infrared spectrometric method for the accurate determination of isolated trans isomers in animal and vegetable fats and oils when trans levels are ≥ 5%. The method measures the C–H deformation band at 966 cm⁻¹, characteristic of isolated trans double bonds, and is adopted by CEN for use across European standards bodies.

Key topics and technical requirements

• Analyte and scope
  • Long-chain fatty acids, fatty acid esters and triglycerides with isolated (non-conjugated) trans bonds.
  • Not applicable (or only with precautions) to materials with >5% conjugated unsaturation (e.g., tung oil), functional groups that alter the 966 cm⁻¹ band (e.g., ricinoleic/ricinelaidic acids), mixed long/short-chain triglycerides, or other interfering absorptions.
• Principle
  • Quantification is based on the IR absorption maximum at 966 cm⁻¹ (C–H deformation of isolated trans double bond).
  • For higher accuracy, samples are converted to methyl esters prior to measurement to eliminate glycerol and carboxyl interferences.
• Instrumentation
  • FT‑IR or dispersive IR spectrometer capable of 4 cm⁻¹ resolution over 1050–900 cm⁻¹.
  • Liquid sampling cells with NaCl or KBr windows and 1 mm path length; matched cells or beam balancing required.
• Reagents and standards
  • Dry carbon disulfide (CS2) solvent (handle with ventilation).
  • Primary standards: methyl elaidate and methyl oleate (≈99% purity).
  • Calibration prepared across multiple trans levels (1%, 4%, 7%, 10%, 30%, 50%, 70%) using specified stock solutions.
• Calibration & procedure
  • Baseline-corrected absorbance at 966 cm⁻¹ is plotted vs. grams of methyl elaidate per 10 ml; regression used for quantification.
  • Sample methylation per ISO 5509 and sample preparation per ISO 661 are referenced.

Applications and users

• Practical for food and oil quality control, processing evaluation (e.g., partial hydrogenation effects), and nutritional labeling where trans content ≥ 5% is relevant.
• Primary users: analytical laboratories, edible oil producers, regulatory agencies, research labs studying lipid isomerization and processing effects.
• Not recommended where conjugated dienes or interfering functional groups are present without specific validation.

Related standards

• ISO 5509 - Preparation of methyl esters of fatty acids (referenced for methylation).
• ISO 661 - Preparation of test sample for fats and oils.
• ISO 15304 - Recommended capillary GLC method for accurate determinations when trans levels are