Chemical characterisation of the vapour emitted by an e-cigarette using a ceramic wick-based technology

Abstract

Fourth-generation ‘pod’ e-cigarette devices have been driven by technological advances in electronic atomization of the e-liquid. Use of microporous ceramic as a wicking material improves heating efficiency, but how it affects the chemical emissions of these devices is unclear. We assessed the emissions of a pod e-cigarette with innovative ceramic wick-based technology and two flavoured e-liquids containing nicotine lactate and nicotine benzoate (57 and 18 mg mL−1 nicotine, respectively). Among the studied harmful and potentially harmful constituents (HPHCs) listed by the US FDA and/or WHO TobReg, only 5 (acetone, acetaldehyde, formaldehyde, naphthalene and nornicotine) were quantified at levels of 0.14 to 100 ng puff−1. In the combustible cigarette (Kentucky reference 1R6F), levels were from 0.131 to 168 µg puff−1. Nicotine levels ranged 0.10–0.32 mg puff−1 across the 3 study products. From the 19 proposed HPHCs specifically of concern in e-cigarettes, only 3 (glycerol, isoamyl acetate and propylene glycol) were quantified. The low/undetectable levels of HPHCs reflect not only the optimal operating conditions of the e-cigarette, including an efficient supply of e-liquid by the ceramic wick without overheating, but also the potential of the e-cigarettes to be used as an alternative to combustible cigarettes.

Nontargeted Analysis in Tobacco Research: Challenges and Opportunities

“…Since data analysis is a critical step in NTA that can have a significant effect on the study outcomes, different peak deconvolution software has been integrated into the analytical workflow in the HTP studies for effective and efficient compound identification. This type of software uses retention times and peak areas, , to match the peaks with established libraries, a process known as spectral matching. − , Unlike targeted analysis where direct quantification is done using an authentic standard for each compound present in the sample matrix, NTA often uses a semiquantification approach to determine the quantities of the identified compounds. Semiquantification methods on HTP were done by constructing an external calibration curve using standards that represent different chemical classes rather than authentic standards for each compound. , …”

“…NTA is a promising technique that can generate this much-needed data. Targeted methods can only identify a limited number of established tobacco-related toxicants and may require the use of a significant number of standard solutions, which may not be readily available or can be expensive to purchase. , However, the identification of those toxicants in addition to product-specific toxicants could inform toxicity assessment of tobacco products, especially ATPs that are widely used in the population . Some studies have reported the presence of novel compounds in ATP emissions that would have been overlooked using targeted analysis.…”

“…This type of software uses retention times and peak areas, 40,52 to match the peaks with established libraries, a process known as spectral matching. [37][38][39]52 Unlike targeted analysis where direct quantification is done using an authentic standard for each compound present in the sample matrix, NTA often uses a semiquantification approach to determine the quantities of the identified compounds. Semiquantification methods on HTP were done by constructing an external calibration curve using standards that represent different chemical classes rather than authentic standards for each compound.…”

An in vitro toxicological assessment of two electronic cigarettes: E-liquid to aerosolisation

“…In the presence of metabolic activation, for RTKN (DNA damage endpoint), ePen showed a positive dose related response while no such response was observed for ePod captured aerosol under any treatment condition. Previous chemical analysis has not reported any significantly higher levels in undesired constituents for ePen ( Margham et al, 2016 , Cunningham et al, 2020 , Pinto et al, 2022 ), making it difficult to ascertain what is driving this response. For example, although a positive RTKN - DNA damaging endpoint was observed in ToxTracker, it is not clear whether this response is transitory in nature and whether the cells can recover, which is an inherent limitation of the in vitro setting and screening nature of the study.…”

Carbonyls and Aerosol Mass Generation from Vaping Nicotine Salt Solutions Using Fourth- and Third-Generation E-Cigarette Devices: Effects of Coil Resistance, Coil Age, and Coil Metal Material

“…Indeed, most studies in the literature have focused on the first-, second-, third-generation or surrogate vaping devices. ,− , Recent studies on 4th gen devices characterized a range of potentially harmful compounds (carbon monoxide, polycyclic aromatic hydrocarbons, carbonyls, metals), − suggesting that the higher-resistance pods and pod-mods may not necessarily offer the benefit of increased nicotine aerosolization without harmful side products. A systematic investigation of aerosol mass and normalized carbonyl formation (from both thermal and ROS-derived mechanisms) in 4th gen devices as a function of coil resistance, age, and material is needed.…”