ISO 10540-3:2002

Overview

ISO 10540-3:2002 specifies a laboratory method for the determination of phosphorus content in animal and vegetable fats and oils using inductively coupled plasma optical emission spectroscopy (ICP-OES). The procedure is designed for oils with low phosphorus content that are clear (no turbidity or visible sediment) and where phosphorus is present in a solubilized form. The method supports most vegetable oil types (crude, degummed, refined, bleached, deodorized, hardened) and nearly all lecithins and phosphatides depending on dilution solvent.

Key topics and technical requirements

• Analytical technique: ICP-OES (direct aspiration of solvent-diluted oils). Phosphorus emission lines commonly used: 178.2 nm, 213.6 nm, 214.9 nm. Typical LOD ≈ 0.5 mg/kg.
• Sample preparation: Dilute samples, standards and blanks 1:1 by mass with solvent (preferred 1‑butanol, or kerosene/xylene). Solid/hardened fats are melted (~10 °C above melting point) and kept ≤ 60 °C during analysis.
• Test aliquot: Example procedure-weigh 2.50 g sample and add 2.50 g solvent; invert/mix and analyze. Lecithins require specific dilute-and-mix steps (see standard).
• Standards and calibration: Prepare organic-soluble phosphorus standards in blank oil; recommended calibration range 0–25 mg/kg with typical standards at 2.5, 5.0, 10.0 mg/kg. Scan blanks, samples and standards in triplicate; restandardize every ~10 samples.
• Instrument considerations: Follow manufacturer specs; adjust pump flow and nebulizer settings for chosen solvent. Monitor for calibration drift (carbon build-up on injector can affect results).
• Limitations: Not suitable when phosphorus is present as fine particles (e.g., bleaching earth). For particulate phosphorus, ISO 10540-2 (graphite furnace AAS) is the appropriate non-ashing direct method.
• Precision: Precision and reproducibility were established by interlaboratory studies (see Annex A). Repeatability and reproducibility limits are provided for tested concentration ranges.

Applications and users

Who uses ISO 10540-3:2002:

• Quality control and analytical laboratories in edible oil, oilseed and lecithin production
• Food manufacturers and ingredient suppliers verifying phosphorus specifications
• Regulatory and compliance labs testing product release and labeling
• R&D and method validation teams evaluating degumming and refining efficiency

Practical uses:

• Monitoring degumming/phosphatide removal during oil refining
• Verifying low-phosphorus specifications for refined oils and lecithins
• Routine QC testing for edible oils and industrial fat streams

Related standards

• ISO 10540-1 - Colorimetric method for phosphorus
• ISO 10540-2 - Graphite furnace atomic absorption spectrometry (GFAAS) for particulate phosphorus
• ISO 661 - Preparation of test sample
• ISO 5555 - Sampling of fats and oils
• ISO 5725 - Method precision (repeatability and reproducibility)

Keywords: ISO 10540-3:2002, phosphorus determination, ICP-OES, animal and vegetable fats and oils, 1-butanol dilution, lecithins, low phosphorus analysis.