Impact of e-Liquid Composition, Coil Temperature, and Puff Topography on the Aerosol Chemistry of Electronic Cigarettes
Impact of e-Liquid Composition, Coil Temperature, and Puff Topography on the Aerosol Chemistry of Electronic Cigarettes
复制标题
DOI：
10.1021/acs.chemrestox.1c00070
复制
发表时间：
2021-05-05
影响因子：
4.1
通讯作者：
Nguyen, Tran B.
中科院分区：
文献类型：
--
作者：
Li, Yichen;Burns, Amanda E.;Nguyen, Tran B.
电子烟气溶胶是气体和颗粒的复杂混合物，其组成取决于电子烟液配方、抽吸方案和设备操作参数。这项工作研究了来自第三代设备的主流气溶胶，作为线圈温度（315-510华氏度或157-266摄氏度）、抽吸持续时间（2-4秒）和电子液体中丙二醇（PG）与植物甘油（VG）的比率（100：0-0：100）的函数。使用液相色谱高分辨率质谱法、气相色谱法、原位化学电离质谱法和重量分析法进行靶向和非靶向分析，用于化学表征。PG和VG是气溶胶两相中的主要成分（>99%）。在测试条件下，观察到大多数电子烟组分是挥发性或半挥发性的。PG被发现几乎完全在气相中，而VG有相当大的颗粒成分。尼古丁仅在颗粒相中观察到。气溶胶质量和羰基降解产物的产生随着较高的盘管温度和抽吸持续时间而显著增加，但随着电子液体中VG分数的增加而降低。一个例外是丙烯醛，它随着VG的增加而增加。羰基化合物的形成在所研究的温度范围内以热诱导脱水机制为主，但自由基反应也发挥了重要作用。这项研究的结果确定了关于这两种途径的开放性问题。在所有测试条件下，电子烟过程消耗PG的速度明显快于VG，这表明随着电子烟的继续，电子烟液体变得更富含VG，并且暴露于丙烯醛的程度显著增加。可以估计，当60-70%的电子烟液在375华氏度（191摄氏度）下的蒸汽烟过程期间剩余时，电子烟液中PG：VG的30：70初始比率几乎完全变成VG。这项工作强调了进一步研究电子烟的抽吸生命周期的必要性。
E-cigarette aerosol is a complex mixture of gases and particles with a composition that is dependent on the e-liquid formulation, puffing regimen, and device operational parameters. This work investigated mainstream aerosols from a third generation device, as a function of coil temperature (315-510 degrees F, or 157-266 degrees C), puff duration (2-4 s), and the ratio of propylene glycol (PG) to vegetable glycerin (VG) in e-liquid (100:0-0:100). Targeted and untargeted analyses using liquid chromatography high-resolution mass spectrometry, gas chromatography, in situ chemical ionization mass spectrometry, and gravimetry were used for chemical characterizations. PG and VG were found to be the major constituents (>99%) in both phases of the aerosol. Most e-cigarette components were observed to be volatile or semivolatile under the conditions tested. PG was found almost entirely in the gas phase, while VG had a sizable particle component. Nicotine was only observed in the particle phase. The production of aerosol mass and carbonyl degradation products dramatically increased with higher coil temperature and puff duration, but decreased with increasing VG fraction in the e-liquid. An exception is acrolein, which increased with increasing VG. The formation of carbonyls was dominated by the heat-induced dehydration mechanism in the temperature range studied, yet radical reactions also played an important role. The findings from this study identified open questions regarding both pathways. The vaping process consumed PG significantly faster than VG under all tested conditions, suggesting that e-liquids become more enriched in VG and the exposure to acrolein significantly increases as vaping continues. It can be estimated that a 30:70 initial ratio of PG:VG in the e-liquid becomes almost entirely VG when 60-70% of e-liquid remains during the vaping process at 375 degrees F (191 degrees C). This work underscores the need for further research on the puffing lifecycle of e-cigarettes.