Overview
ISO 23921:2020 specifies a validated analytical method for quantifying four tobacco-specific nitrosamines (TSNAs) in mainstream cigarette smoke using reversed-phase HPLC coupled with tandem mass spectrometry (LC‑MS/MS). The method targets N‑nitrosonornicotine (NNN), N‑nitrosoanatabine (NAT), N‑nitrosoanabasine (NAB) and NNK, and applies to the total particulate matter collected under the intense smoking regime defined in ISO 20778. ISO 23921:2020 provides detailed procedures for sampling, extraction, chromatography, mass spectrometry and calculation to ensure reproducible TSNA measurements.
Key Topics and Requirements
- Analytes: NNN, NAT, NAB, NNK (TSNAs) in cigarette mainstream smoke.
- Smoking regime: Intense machine smoking per ISO 20778 (Health Canada T‑115 equivalent).
- Collection: Mainstream smoke trapped on glass‑fibre filter pads (44 mm for linear, 92 mm for rotary).
- Sample preparation: Addition of isotopically labeled internal standards (deuterated NNN‑d4, NAT‑d4, NAB‑d4, NNK‑d4), extraction with 100 mM ammonium acetate, shaking, and syringe filtration through 0.45 µm PTFE filters into autosampler vials.
- Chromatography & detection: Reversed‑phase HPLC and LC‑MS/MS quantitation; example LC column cited (Waters XBridge BEH C18, 2.5 µm, 2.1 × 50 mm) or equivalent.
- Calibration & quantification: Preparation of calibration standards, use of internal standards, calibration curve construction and sample quantification procedures.
- Quality & performance: Procedures include repeatability and reproducibility assessments and comprehensive test reporting requirements.
- Safety & contamination control: Clean glassware, reagent grades, and controlled laboratory practice are mandated.
Applications and Who Uses It
ISO 23921:2020 is used by:
- Regulatory laboratories assessing product emissions for compliance and comparative evaluation.
- Tobacco industry R&D and QC laboratories for product development and batch testing.
- Analytical and environmental chemistry labs conducting targeted TSNA exposure research.
- Public health and academic researchers studying smoke chemistry and toxicant inventories.
Practical benefits include robust, reproducible TSNA data for regulatory submissions, inter‑laboratory comparability, method harmonization, and high‑sensitivity detection using LC‑MS/MS.
Note: Machine smoking regimes characterize emissions under defined conditions but do not directly represent human exposure or risk.
Related Standards
- ISO 20778 - Routine analytical cigarette smoking machine (intense smoking regime)
- ISO 20779 - Generation and collection of total particulate matter (intense regime)
- ISO 3402 - Conditioning and testing atmosphere for tobacco
- ISO 8243 - Cigarette sampling
- ISO 5725 - Accuracy (repeatability and reproducibility) of measurement methods
Keywords: ISO 23921:2020, TSNAs, LC‑MS/MS, NNN, NNK, mainstream cigarette smoke, intense smoking regime, HPLC, tobacco analytical method.