E-cigarettes are often promoted as a “healthy” alternative to cigarettes (“The Promise of Vaping and the Rise of Juul” New Yorker, 14 May 2018). The public health appeal of this is simple: nicotine is notoriously addictive (even without the flavorings that Juul adds), so vaping is offered as a way for smokers to self-administer nicotine without exposing themselves to tobacco and carcinogens.
If only life were that simple. Nicotine has its own toxicity problems. Juul has become the e-cigarette/addiction of choice among teens who had not been smokers or nicotine addicts previously, and there are very real concerns about Juul being a stepping stone to cigarettes, let alone an addiction that works on teenagers’ still-developing brain networks.
Now a team of chemists at Portland State University (Angela Duell, James Pankow, David Peyton) provides a possible reason why Juul’s brand of nicotine liquid might be unusually appealing and addictive. Juul adds more acid to its liquid to create more protonated nicotine than other brands, and this form of nicotine is more appealing when inhaled. (Background chemistry: The nicotine molecule contains 2 basic nitrogen atoms, and nicotine solutions contain a “free base” form in which both N are electrically neutral, and “protonated” form in which one N remains neutral and the other carries an extra proton as R3NH+.)
Earlier investigations of the free and protonated nicotine in Juul’s liquids had not given reliable results, but the PSU team found a way around this experimental hurdle. Links to the PSU research include: Chem. Res. Toxicol. 2018, DOI: 10.1021/acs.chemrestox.8b00097 | C&ENews, 2018, 96(22), 28 May