Overview
ISO 3401:1991 - Cigarettes - Determination of alkaloid retention by the filters - Spectrometric method - specifies two spectrometric procedures (a direct method and an indirect method) for measuring the alkaloids retained by cigarette filters, expressed as nicotine. The standard describes principle, reagents, apparatus, sampling, test procedures, calculation of results and reporting. The direct method is preferred except where filter materials (for example some charcoal filters) prevent complete recovery; the indirect method has limitations (not suitable for cigarettes with perforated or porous filter tipping wraps).
Key topics and technical requirements
- Methods defined:
- Direct method - remove filter tips, extract and subject to steam distillation (acid then alkaline), collect distillate and determine alkaloids by spectrometric absorbance.
- Indirect method - compare mainstream smoke alkaloid content from intact filter cigarette vs the same cigarette with filter material removed; used when direct recovery is incomplete.
- Reagents: methanol; NaOH solution (c = 8 mol/L); sulfuric acid solutions (1 mol/L and 0.025 mol/L); nicotine reference (≥98% purity).
- Apparatus: routine lab glassware plus steam distillation apparatus (50–100 ml distillation chamber with steam inlet and jacketed condenser), spectrometer covering 230–290 nm, quartz cells (1 cm path), volumetric flasks, routine analytical smoking machine and glass-fibre traps per ISO 3308 and ISO 4387.
- Sampling and conditioning: samples prepared and conditioned per ISO 8243 and ISO 3402; smoking performed on routine analytical smoking machines per ISO 3308 and ISO 4387.
- Results and reporting: report alkaloid (as nicotine) in mg per cigarette for mainstream condensate and retained by filter (to 0.01 mg), and mean alkaloid retention index (%) to nearest 1%; include test conditions and full sample identification.
Practical applications and users
- Who uses it: tobacco product testing laboratories, quality control teams in cigarette manufacturing, regulatory and compliance laboratories, and research groups studying filter efficiency or nicotine delivery.
- Use cases:
- Quantifying nicotine/alkaloid retention efficiency of different filter designs or materials.
- Supporting product development and comparative performance testing (including activated charcoal vs standard filters).
- Generating data for regulatory submissions and quality assurance.
Related standards
- ISO 3308 - Routine analytical cigarette-smoking machine (definitions & conditions)
- ISO 3400 - Determination of alkaloids in smoke condensates - spectrometric method
- ISO 3402 - Conditioning and testing atmosphere for tobacco products
- ISO 4387 - Determination of total particulate matter using smoking machines
- ISO 8243 - Cigarettes - Sampling
Keywords: ISO 3401:1991, alkaloid retention, cigarette filters, spectrometric method, nicotine retention, smoking machine, steam distillation, filter cigarette testing.