Determination of Ammonia in Tobacco Smoke

Importance of the Topic

Cigarette manufacturers add ammonia to tobacco both naturally and intentionally to enhance flavor and to freebase nicotine, increasing its bioavailability in smoke inhaled by smokers and bystanders
The U.S. FDA now requires quantification of harmful and potentially harmful constituents in tobacco products, including ammonia, under the Family Smoking Prevention and Tobacco Control Act
A sensitive and selective analytical approach is essential to meet regulatory demands and to avoid interferences from other amine species present in tobacco smoke

Objectives and Study Overview

This application note describes the development of an ion chromatography (IC) method for the determination of ammonia in mainstream and sidestream tobacco smoke extracts
The main goals were to

• Achieve baseline resolution of ammonium from low-molecular-weight amines such as methylamine and ethylamine
• Eliminate laborious manual eluent preparation
• Provide robust and reproducible quantification with low detection limits suitable for regulatory compliance

Methodology and Instrumentation

Sample Preparation

• Reference cigarette smoke extracts (3R4F) captured in 50 mN sulfuric acid
• Injection of acid extracts without dilution

Chromatographic Conditions

• System: Thermo Scientific Dionex ICS-5000+ HPIC with RFIC and autosuppressor
• Columns: CG19 guard (2×50 mm) and CS19 analytical (2×250 mm) carboxylate-functionalized cation-exchange
• Eluent: Electrolytically generated methanesulfonic acid (5 mM for 7 min, 50 mM for 7.1–16 min, 5 mM for 16.1–24 min)
• Flow rate: 0.25 mL/min; injection volume: 5 µL
• Column temperature: 30 °C; suppressor: Dionex CSRS 300 in recycle mode at 37 mA

Main Results and Discussion

Chromatographic Performance

• Ammonium elutes at ~6 min with resolutions of ≥1.6 from sodium and ≥1.7 from methylamine
• Total run time per injection: 24 min

Calibration and Sensitivity

• Linear response (R2 = 0.9976) up to 2 mg/L; quadratic fit (R2 = 0.9993) to 10 mg/L
• Limit of detection: 0.003 mg/L (S/N = 3); limit of quantitation: 0.01 mg/L (S/N = 10)

Precision and Accuracy

• Retention time RSD ≤0.11%; peak area RSD <1%
• Recovery in spiked smoke samples ranged from 86% to 115%

Robustness

• Over 370 injections per column, retention time drift was –1.0% to –1.6%, with stable peak area
• Comparable performance across column lots

Benefits and Practical Applications

This IC method

• Provides robust separation of ammonium from interfering amines in complex smoke matrices
• Uses RFIC to automate eluent generation, reducing preparation errors and labor
• Employs a 2 mm column format, lowering solvent consumption and waste
• Delivers reproducible results suitable for routine quality control and regulatory monitoring

Future Trends and Opportunities

Advances may include

• Integration of higher-throughput or multiplexed IC systems for large sample loads
• Coupling with mass spectrometry for confirmatory analysis of smoke constituents
• Further miniaturization and green chromatography approaches to reduce waste

Conclusion

The described Dionex IC method with RFIC-generated methanesulfonic acid and CS19 columns achieves accurate, sensitive, and interference-free determination of ammonia in tobacco smoke extracts, fulfilling regulatory requirements with minimal operator maintenance

Used Instrumentation

• Thermo Scientific Dionex ICS-5000+ HPIC system with SP single pump or DP double pump
• Dionex EG Eluent Generator and EGC III MSA cartridge
• Dionex CR-CTC II self-regenerating cation trap column
• Dionex IonPac CG19 guard (2×50 mm) and CS19 analytical (2×250 mm) columns
• Dionex CSRS 300 Cation Self-Regenerating Suppressor in recycle mode
• Dionex AS-AP Autosampler and Chromeleon CDS software

References

1. van Amsterdam J; Sleijffers A; van Spiegel P; Blom R; Witte M; van de Kassteele J; Blokland M; Steerenberg P; Opperhuizen A. Effect of Ammonia in Cigarette Tobacco on Nicotine Absorption in Human Smokers. Food Chem Toxicol. 2011,49,3025–3030.
2. Stevenson T; Proctor RN. The Secret and Soul of Marlboro. Am J Public Health. 2008,98,1184–1194.
3. Willems EW; Rambali B; Vleeming W; Opperhuizen A; van Amsterdam J. Significance of Ammonium Compounds on Nicotine Exposure to Cigarette Smokers. Food Chem Toxicol. 2006,44,678–688.
4. U.S. Food and Drug Administration. Harmful and Potentially Harmful Constituents in Tobacco Products and Tobacco Smoke; Established List. Fed Regist. 2012,77(64),20034–20037.
5. Nanni EJ; Lovette ME; Hicks RD; Fowler KW; Borgerding MF. Separation and Quantitation of Monovalent Anionic and Cationic Species in Mainstream Cigarette Smoke Aerosols by High-Performance Ion Chromatography. J Chromatogr Sci. 1990,28,432–436.
6. CORESTA Recommended Method No. 73. Cooperation Centre for Scientific Research Relative to Tobacco. Paris, France, 2011.
7. Official Method T-302: Determination of Ammonia in Whole Tobacco. Canada Dept. of Health, 1999.
8. Official Method T-201: Determination of Ammonia in Sidestream Tobacco Smoke. Canada Dept. of Health, 1999.
9. British American Tobacco Group R&D. Determination of Ammonia in Mainstream Smoke. 2008.