Overview
ISO/TR 18818:2017 specifies a rapid screening and quantitative analytical method for detecting Diethanolamine (DEA) in cosmetics and cosmetic raw materials using gas chromatography–mass spectrometry (GC‑MS). It is designed as a simple extraction + GC‑MS workflow for confirmation and quantification of DEA at or above the method’s limit of quantification (LoQ) of 1 000 mg/kg (0.1%). The method is not applicable to DEA‑related ingredients and users must verify applicability for unfamiliar sample matrices.
Key topics and technical requirements
- Scope: Screening and quantification of free DEA in cosmetics/raw materials only; DEA‑related compounds are excluded.
- Sample preparation:
- Weigh ~1.0 g sample and extract with ethanol (5.0 mL), ultrasonic treatment (~15 min), bring to 10 mL, centrifuge (≈6 000 r/min, 10 min).
- Drying agent: add ~1.5 g anhydrous sodium sulfate (Na2SO4) and filter through 0.45 µm membrane prior to GC‑MS.
- Calibration and standards:
- Stock solution example: 5 000 µg/mL DEA; intermediate 1 000 µg/mL; calibration range example 50–500 µg/mL.
- Calibration curve based on peak area vs. concentration using the quantitative ion m/z 74 in SIM mode; required correlation coefficient R > 0.990.
- Typical recovery for spiked samples (100–500 µg) should be ≥ 90%.
- GC‑MS parameters (example conditions):
- Injection: 1 µL, split 30:1; columns suggested (DB‑624 or Rx‑5 ms type); electron ionization 70 eV; EI scan 28–300 amu; monitoring ions include m/z 74 (quant), 56, 45, 30.
- Limitations:
- LoQ = 1 000 mg/kg (0.1%). Samples with lower DEA levels, unusual matrices or matrix interferences (e.g., peak tailing) may require alternate methods or confirmatory testing.
- Quantification: Concentration in sample solution combined with final volume, sample mass and any dilution factor yields mass fraction (%) of DEA.
Applications and users
- Quality control and screening in cosmetic formulation and raw‑material testing labs
- Regulatory and safety testing laboratories assessing compliance with jurisdictional DEA restrictions
- Contract analytical laboratories performing GC‑MS screening for manufacturers and suppliers
- Cosmetic R&D when verifying absence/presence of residual DEA in ingredients
Related standards and methods
- ISO/TR 18818:2017 complements other analytical approaches for alkanolamines such as LC‑MS/MS, derivatization‑based HPLC methods and standards referenced in the bibliography (e.g., ASTM D7599‑09, SN/T 2107‑2008). Users may select alternative validated methods when lower LoQ or different matrices are required.
Keywords: ISO/TR 18818:2017, Diethanolamine, DEA, GC‑MS, cosmetics, analytical method, limit of quantification, SIM m/z 74, sample preparation, calibration.