Overview
ISO 22303:2008 specifies a laboratory method for the determination of tobacco specific nitrosamines (TSNAs) - N‑nitrosonornicotine (NNN), N‑nitrosoanatabine (NAT), N‑nitrosoanabasine (NAB) and 4-(methylnitrosamino)-1-(3‑pyridyl)-1‑butanone (NNK) - in ground leaf tobacco, manufactured tobacco and tobacco products. The standard defines a buffer extraction procedure followed by organic elution, concentration and quantification by gas chromatography with chemiluminescence detection. It is published by ISO as ISO 22303:2008.
Key topics and technical requirements
- Scope: Applicable to ground leaf tobacco, manufactured tobacco and tobacco products for TSNA analysis.
- Extraction principle: TSNAs are extracted into an aqueous buffer, adsorbed onto diatomaceous earth, eluted with dichloromethane (methylene chloride), concentrated under nitrogen and analyzed by GC.
- Buffer composition and preparation: The standard gives a citrate/phosphate/ascorbic acid buffer (prepared for 2 L) with pH ~4.3 and recommends weekly preparation and 4 °C storage.
- Internal standard and calibration: N‑nitrosodi‑n‑hexylamine (NDHA) is used as internal standard. Calibration requires at least four concentration levels and linear regression with correlation coefficient R² > 0.990 for each analyte.
- Instrument configuration: GC in splitless mode fitted with a chemiluminescence detector; typical column specified is fused silica capillary (30 m × 0.53 mm, 3.0 µm dimethylpolysiloxane). Specific oven programs and detector settings are provided.
- Sample procedure: Typical sample mass 1.0 g; sonication with 50 mL buffer for 1 h; diatomaceous earth column cleanup; dichloromethane elution; concentration to ~0.5 mL and final dilution to 2 mL before GC analysis.
- Safety: Nitrosamines are suspected carcinogens - use appropriate PPE (gloves, engineering controls) and follow lab safety practices.
- Documentation: Includes requirements for data analysis, repeatability/reproducibility considerations and test reporting.
Applications and users
- Tobacco industry analytical and quality‑control laboratories validating TSNA content in raw leaf and finished products.
- Regulatory and public‑health laboratories performing compliance testing or surveillance of tobacco products.
- Research institutions studying TSNA formation, mitigation strategies or exposure assessment.
- Contract testing labs offering accredited TSNA analysis services.
Keywords: ISO 22303:2008, tobacco specific nitrosamines, TSNAs, gas chromatography chemiluminescence, buffer extraction, NNN, NNK, NAB, NAT, NDHA.
Related standards
- ISO/TS 22304 - alternative method using alkaline dichloromethane extraction (referenced in ISO 22303 introduction).
- ISO 1042 (laboratory volumetric flasks) and ISO 3696 (water for analytical use) are normative references cited in ISO 22303.
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