ISO 15774:2017

Overview

ISO 15774:2017 specifies a laboratory method for the determination of trace amounts of cadmium (µg/kg level) in all types of crude or refined edible oils and fats using direct graphite furnace atomic absorption spectrometry (GFAAS). The standard covers sample treatment, apparatus, reagents, calibration and quality criteria for reporting results. Note: fat from milk and milk products is explicitly excluded from the scope.

Key Topics

• Scope and purpose: Quantitative determination of cadmium in edible oils/fats at microgram-per-kilogram concentrations.
• Analytical principle: Samples are incinerated and atomized in a graphite tube furnace; absorption is measured at 228.8 nm. Palladium is used as a matrix modifier to prevent Cd loss during thermal pretreatment.
• Reagents and standards:
  • Type 1 laboratory water (ISO 3696)
  • Cyclohexane and hydrochloric acid
  • Palladium chloride; matrix modifier prepared as 0.1% (m/v) Pd solution
  • Organometallic cadmium standard (example: Conostan) and prepared stock/working solutions (working levels 2.5, 5.0 and 10.0 µg/kg)
• Apparatus:
  • Atomic absorption spectrometer with graphite furnace, platform (pyrolytic), uncoated graphite tubes, deuterium or Zeeman background correction, and optional autosampler with heated sample cups.
• Sample preparation & injection:
  • Keep samples/standards at 60 °C prior to analysis.
  • Autosampler with heating: inject 15 µl; without heating dilute 1:1 (mass/volume) with cyclohexane and inject 20 µl.
  • Fat samples with melting point ≥40 °C: dilute 1:1 (mass) with blank oil and use an extra temperature program step.
  • Typical injection volumes: 20 µl matrix modifier then 10 µl sample for manual pipetting.
• Calibration & quality: Calibrate using the three working standards; perform two determinations and report the mean. Precision data (repeatability and reproducibility limits) are given for specified concentration ranges.

Applications and Users

• Who uses it:
  • Food and feed testing laboratories
  • Regulatory and public health agencies monitoring heavy metals
  • Quality control teams in edible oil and fat production and refining
  • Contract analytical laboratories and accreditation bodies
• Practical uses:
  • Routine monitoring for cadmium contamination in edible oils (raw and refined)
  • Compliance testing against national/regional Cd limits
  • Method transfer, validation and interlaboratory comparisons for oil matrices

Related Standards

• ISO 3696 - Water for analytical laboratory use (referenced for reagent water quality).
• Users should follow laboratory quality/validation practices and cite ISO 15774:2017 in test reports as required by the standard.

Keywords: ISO 15774:2017, cadmium determination, graphite furnace atomic absorption spectrometry, GFAAS, edible oils and fats, trace cadmium, food safety testing.