Overview
EN ISO 10565:1998 (ISO 10565:1998) specifies a rapid, laboratory method for the simultaneous determination of oil and water contents in oilseeds using pulsed nuclear magnetic resonance (NMR) spectrometry. The method is applicable to rapeseed, soybean, linseed and sunflower seed when moisture is below 10% (samples with higher moisture must be dried before oil measurement). The standard was prepared by ISO/TC 34 (oleaginous seeds) and adopted by CEN.
Key topics and technical requirements
- Principle: uses pulsed NMR pulses (90° RF pulse to record free induction decay (FID) and 180° pulse to produce a spin-echo) to separate oil and water proton signals. Oil echo amplitude is proportional to oil content; difference between amplitudes gives water content.
- Instrumentation: pulsed low‑resolution NMR spectrometer, glass sample tubes, electronic analytical balance (±0.01 g), drying oven (103 °C ±2 °C), desiccator. Follow manufacturer settings and safety (remove metallic objects).
- Calibration:
- Minimum three calibration points (or single-sample procedures varying fill height) for both oil and water calibrations.
- Calibration correlation coefficient normally > 0.95.
- Minimum total measurement time per calibration: 16 s.
- Oil calibration includes a zero-point check (empty tube).
- Sample preparation and measurement:
- Reduce laboratory sample as per ISO 664; sampling guidance referenced (ISO 542).
- Condition samples 60 min in test room at 17–28 °C.
- Prepare test portions of constant volume or to manufacturer-recommended fill height (examples for 30 mm: rapeseed 22–25 g, sunflower 14–17 g, soybeans 21–24 g).
- Carry out at least two determinations per test sample and verify calibration at start of series (daily minimum).
- Limitations and precision:
- Method tested on rapeseed, soybean, linseed and sunflower; may apply to other seeds with liquid oil at measurement temperature.
- Reproducibility is generally higher (i.e., worse) than the reference drying method (ISO 665).
Applications and users
This standard is practical for:
- Quality control laboratories in oilseed processing and crushing plants
- Seed testing and certification bodies
- Agricultural laboratories monitoring seed moisture and oil yield
- Plant breeding and research labs tracking oil content
- Instrument manufacturers and service engineers validating pulsed NMR setups
Benefits include rapid throughput, simultaneous oil and moisture data, and non-destructive sample analysis when moisture is within method limits.
Related standards
- ISO 659 - Determination of hexane extract (“oil content”)
- ISO 664 - Reduction of laboratory sample to test sample
- ISO 665 - Determination of moisture and volatile matter (reference drying method)
- ISO 542 - Recommended sampling procedures
Keywords: EN ISO 10565:1998, ISO 10565, pulsed NMR, oilseeds, oil content, water content, rapeseed, soybean, sunflower seed, linseed, seed testing, oilseed quality.