Baassiri Mohammad, Talih Soha, Salman Rola, Karaoghlanian Nareg, Saleh Rawad, El Hage Rachel, Saliba Najat, Shihadeh Alan
Department of Mechanical Engineering, Faculty of Engineering and Architecture, University of Beirut, Beirut, Lebanon.
Department of Chemistry, Faculty of Arts and Sciences, American University of Beirut, Beirut, Lebanon.
Aerosol Sci Technol. 2017;51(11):1231-1239. doi: 10.1080/02786826.2017.1341040. Epub 2017 Jun 30.
Electronic cigarettes (ECIGs) heat and vaporize a liquid mixture to produce an inhalable aerosol that can deliver nicotine to the user. The liquid mixture is typically composed of propylene glycol (PG) and vegetable glycerin (VG), in which are dissolved trace quantities of flavorants and, usually, nicotine. Due to their different chemical and thermodynamic properties, the proportions of PG and VG in the liquid solution may affect nicotine delivery and user sensory experience. In social media and popular culture, greater PG fraction is associated with greater "throat-hit", a sensation that has been attributed in cigarette smokers to increased presence of vapor-phase nicotine. VG, on the other hand, is associated with thicker and larger exhaled "clouds". In this study, we aim to investigate how PG/VG ratio influences variables that relate to nicotine delivery and plume visibility. Aerosols from varying PG/VG liquids were generated using a digitally controlled vaping instrument and a commercially available ECIG, and analyzed for nicotine content by GC-MS. Particle mass and number distribution were determined using a six-stage cascade impactor and a fast particle spectrometer (TSI EEPS), with tightly controlled dilution and sampling biases. A Mie theory model was used to compute the aerosol scattering coefficients in the visible spectrum. Decreasing the PG/VG ratio resulted in a decrease in total particulate matter (TPM) and nicotine yield (R > 0.9, <.0001). Measured particle count median diameter ranged between 44-97nm, and was significantly smaller for PG liquids. Although the particle mass concentration was lower, aerosols produced using liquids that contained VG had an order of magnitude greater light scattering coefficients. These findings indicate that PG/VG ratio is a strong determinant of both nicotine delivery and user sensory experience.
电子烟通过加热并汽化一种液体混合物来产生可吸入的气溶胶，从而将尼古丁递送给使用者。该液体混合物通常由丙二醇（PG）和蔬菜甘油（VG）组成，其中溶解有微量的调味剂，通常还有尼古丁。由于它们不同的化学和热力学性质，液体溶液中PG和VG的比例可能会影响尼古丁的递送和使用者的感官体验。在社交媒体和流行文化中，较高的PG比例与更强的“击喉感”相关，吸烟者将这种感觉归因于气相尼古丁含量的增加。另一方面，VG与呼出的更浓密、更大的“烟雾”有关。在本研究中，我们旨在探究PG/VG比例如何影响与尼古丁递送和烟雾可见度相关的变量。使用数字控制的电子烟装置和市售电子烟产生来自不同PG/VG液体的气溶胶，并通过气相色谱 - 质谱联用仪（GC-MS）分析尼古丁含量。使用六级串联撞击器和快速粒子光谱仪（TSI EEPS）测定颗粒质量和数量分布，严格控制稀释和采样偏差。使用米氏理论模型计算可见光谱中的气溶胶散射系数。降低PG/VG比例会导致总颗粒物（TPM）和尼古丁产量降低（R > 0.9，<.0001）。测得的颗粒计数中值直径在44 - 97nm之间，PG液体的该值明显更小。尽管颗粒质量浓度较低，但使用含VG的液体产生的气溶胶的光散射系数大一个数量级。这些发现表明，PG/VG比例是尼古丁递送和使用者感官体验的一个重要决定因素。
