Overview
ISO/TS 22304:2008 - "Tobacco - Determination of tobacco specific nitrosamines - Method using alkaline dichloromethane extraction" specifies a laboratory procedure for quantifying the four principal tobacco specific nitrosamines (TSNAs): NNN, NAT, NAB, and NNK. The method uses alkaline dichloromethane extraction of ground leaf tobacco, manufactured tobacco or tobacco products, followed by separation and quantification by gas chromatography (GC) with a chemiluminescence detector. It is an ISO Technical Specification (2008) intended for analytical and quality-control environments.
Key Topics and Requirements
- Analytes covered: N-nitrosonornicotine (NNN), N-nitrosoanatabine (NAT), N-nitrosoanabasine (NAB), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK).
- Principle: Extraction of TSNAs from ~1.5 g ground tobacco using dichloromethane containing NaOH, clean-up through MgSO4/Na2SO4 mixed bed, evaporation, reconstitution in chloroform, and GC separation.
- Detection & quantification: Gas chromatography with chemiluminescence detection; quantification by an internal standard technique using N-nitrosodi-n-hexylamine (NDHA).
- Chromatography details: Example column - fused silica capillary, 30 m × 0.53 mm, 1.5 µm film (5% phenyl methylpolysiloxane). Method set up for splitless injections; detector uses ozone generation (oxygen) and helium carrier gas.
- Standards & calibration: Multi-level calibration (at least four levels) with NDHA as the internal standard; calibration curves expected to yield high linearity (R² > 0.990).
- Sample handling & safety: Nitrosamines are suspected carcinogens - the specification requires appropriate safety precautions (gloves, controlled handling). Standard solutions and extracts are stored at around −20 °C.
- Instrumentation & consumables: Lists required apparatus (GC with chemiluminescence detector, eluent evaporator, vortex mixer, autosampler vials, fritted extraction columns) and reagent grades (dichloromethane, chloroform, NaOH, MgSO4, Na2SO4).
Applications
- Routine analytical testing of tobacco and tobacco products for TSNA content.
- Quality control in tobacco manufacturing to monitor nitrosamine levels during processing and product release.
- Regulatory testing and compliance monitoring where regulators require standardized TSNA measurement.
- Research laboratories investigating formation, mitigation or transfer of nitrosamines in tobacco processing and product formulations.
- Useful for laboratories seeking a faster analysis that uses less solvent compared to buffer-extraction alternatives.
Who Should Use It
- Tobacco industry QC/analytical teams
- Contract and independent analytical laboratories
- Regulatory agencies and public health laboratories
- Academic and industrial researchers studying tobacco chemistry or toxicants
Related Standards
- ISO 22303 - alternative buffer extraction method for TSNAs (referenced within the specification).
- ISO 1042 (laboratory glassware) and ISO 3696 (water for analytical laboratory) - cited normative references in the document.
Keywords: ISO/TS 22304:2008, TSNAs, tobacco specific nitrosamines, NNN, NNK, alkaline dichloromethane extraction, gas chromatography, chemiluminescence detector, NDHA, tobacco testing.
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