Chemical hazards present in liquids and vapors of electronic cigarettes
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Electronic (e-)cigarettes have emerged in recent years as putative alternative to conventional tobacco cigarettes. These products do not contain typical carcinogens that are present in tobacco smoke, due to the lack of combustion. However, besides nicotine, hazards can also arise from other constituents of liquids, such as solvents, flavors, additives and contaminants. In this study, we have analyzed 28 liquids of seven manufacturers purchased in Germany. We confirm the presence of a wide range of flavors to enhance palatability. Although glycerol and propylene glycol were detected in all samples, these solvents had been replaced by ethylene glycol as dominant compound in five products. Ethylene glycol is associated with markedly enhanced toxicological hazards when compared to conventionally used glycerol and propylene glycol. Additional additives, such as coumarin and acetamide, that raise concerns for human health were detected in certain samples. Ten out of 28 products had been declared “free-of-nicotine” by the manufacturer. Among these ten, seven liquids were identified containing nicotine in the range of 0.1–15 µg/ml. This suggests that “carry over” of ingredients may occur during the production of cartridges. We have further analyzed the formation of carbonylic compounds in one widely distributed nicotine-free brand. Significant amounts of formaldehyde, acetaldehyde and propionaldehyde were only found at 150 °C by headspace GC–MS analysis. In addition, an enhanced formation of aldehydes was found in defined puff fractions, using an adopted machine smoking protocol. However, this effect was delayed and only observed during the last third of the smoking procedure. In the emissions of these fractions, which represent up to 40 % of total vapor volume, similar levels of formaldehyde were detected when compared to conventional tobacco cigarettes. By contrast, carbonylic compounds were hardly detectable in earlier collected fractions. Our data demonstrate the necessity of standardized machine smoking protocols to reliably address putative risks of e-cigarettes for consumers.
KeywordsElectronic cigarette Vapor Liquids Ethylene glycol Flavors Formaldehyde
This study was financially supported by intramural funding of the German Federal Institute for Risk Assessment (BfR), SFP Grant No. 1322-535.
- CDC (2013) Notes from the field: electronic cigarette use among middle and high school students—United States, 2011–2012. MMWR Morb Mortal Wkly Rep 62:729–730Google Scholar
- Dawkins L, Concoran O (2014) Acute electronic cigarette use: nicotine delivery and subjective effects in regular users. Psychopharmacology 231:401–407Google Scholar
- European Parliament (2013) Amendments adopted by the European Parliament on 8 October 2013 on the proposal for a directive of the European Parliament and of the Council on the approximation of the laws, regulations and administrative provisions of the Member States concerning the manufacture, presentation and sale of tobacco and related products [COM(2012)0788–C7-0420/2012–2012/0366(COD)]Google Scholar
- Farsalinos KE, Romagna G, Allifranchini E, Ripamonti E, Bocchietto E, Todeschi S, Tsiapras D, Kyrzopoulos S, Voudris V (2013a) Comparison of the cytotoxic potential of cigarette smoke and electronic cigarette vapour extract on cultured myocardial cells. Int J Environ Res Public Health 10:5146–5162PubMedCentralPubMedCrossRefGoogle Scholar
- Farsalinos KE, Romagna G, Tsiapras D, Kyrzopoulos S, Voudris V (2013b) Evaluation of electronic cigarette use (vaping) topography and estimation of liquid consumption: implications for research protocol standards definition and for public health authorities’ regulation. Int J Environ Res Public Health 10:2500–2514PubMedCentralPubMedCrossRefGoogle Scholar
- Hansson J, Galanti MR, Hergens MP, Fredlund P, Ahlbom A, Alfredsson L, Bellocco R, Eriksson M, Hallqvist J, Hedblad B, Janssom JH, Nilsson P, Pedersen N, Lagerros YT, Östergren PO, Magnusson C (2012) Use of snus and acute myocardial infarction: pooled analysis of eight prospective observational studies. Eur J Epidemiol 27:771–779PubMedCrossRefGoogle Scholar
- IARC monographs on the evaluation of carcinogenic risks to humans (1999) Re-evaluation of some organic chemicals, hydrazine and hydrogen peroxide, vol 71. International Agency for Research on Cancer, LyonGoogle Scholar
- Jasinska AJ, Zorick T, Brody AL, Stein EA (2013) Dual role of nicotine in addiction and cognition: a review of neuroimaging studies in humans. Neuropharmacology. doi: 10.1016/j.neuropharm.2013.02.015
- Lee S, Grana RA, Glantz SA (2014) Electronic cigarette use among Korean adolescents: a cross-sectional study of market penetration, dual use, and relationship to quit attempts and former smoking. J Adolesc Health 54:684–690Google Scholar
- Mayer B (2014) How much nicotine kills a human? Tracing back the generally accepted lethal dose to dubious self-experiments in the nineteenth century. Arch Toxicol 88:5–7Google Scholar
- WHO (2004) WHO Study Group on tobacco product regulation. Guiding principles for the development of tobacco research and testing capacity and proposed protocols for the initiation of tobacco product testing, p 11. http://www.who.int/tobacco/global_interaction/tobreg/goa_2003_principles/en/index.html. (Accessed 8 Aug 2013)