Effects of E-Cigarette Flavor Enhancing Capsules on Inhalable Aerosols.

The flavor of inhaled e-cigarette aerosols may be augmented using crushable flavor capsules added to e-cigarettes. For example, Puff Krush contains breakable flavor capsules in a sorbent material. The capsules are crushed, and then, aerosol passes through the saturated sorbent material before inhalation. Herein, we used NMR and GC-MS to identify the capsule medium chain triglyceride (MCT) solvent and flavorants in selected Puff Krush flavor capsules and then determined which molecules from the capsule transfer into aerosols. MCTs from the Puff Krush were not found in the aerosols, and ∼50% of Puff Krush flavorants transferred into the aerosol upon vaping.

Effects of Common e-Liquid Flavorants and Added Nicotine on Toxicant Formation during Vaping Analyzed by 1H NMR Spectroscopy.

A broad variety of e-liquids are used by e-cigarette consumers. Additives to the e-liquid carrier solvents, propylene glycol and glycerol, often include flavorants and nicotine at various concentrations. Flavorants in general have been reported to increase toxicant formation in e-cigarette aerosols, yet there is still much that remains unknown about the effects of flavorants, nicotine, and flavorants + nicotine on harmful and potentially harmful constituents (HPHCs) when aerosolizing e-liquids. Common flavorants benzaldehyde, vanillin, benzyl alcohol, and trans-cinnamaldehyde have been identified as some of the most concentrated flavorants in some commercial e-liquids, yet there is limited information on their effects on HPHC formation. E-liquids containing flavorants + nicotine are also common, but the specific effects of flavorants + nicotine on toxicant formation remain understudied. We used 1H NMR spectroscopy to evaluate HPHCs and herein report that benzaldehyde, vanillin, benzyl alcohol, trans-cinnamaldehyde, and mixtures of these flavorants significantly increased toxicant formation produced during e-liquid aerosolization compared to unflavored e-liquids. However, e-liquids aerosolized with flavorants + nicotine decreased the HPHCs for benzaldehyde, vanillin, benzyl alcohol, and a "flavorant mixture" but increased the HPHCs for e-liquids containing trans-cinnamaldehyde compared to e-liquids with flavorants and no nicotine. We determined how nicotine affects the production of HPHCs from e-liquids with flavorant + nicotine versus flavorant, herein referred to as the "nicotine degradation factor". Benzaldehyde, vanillin, benzyl alcohol, and a "flavorant mixture" with nicotine showed lower HPHC levels, having nicotine degradation factors <1 for acetaldehyde, acrolein, and total formaldehyde. HPHC formation was most inhibited in e-liquids containing vanillin + nicotine, with a degradation factor of ∼0.5, while trans-cinnamaldehyde gave more HPHC formation when nicotine was present, with a degradation factor of ∼2.5 under the conditions studied. Thus, the effects of flavorant molecules and nicotine are complex and warrant further studies on their impacts in other e-liquid formulations as well as with more devices and heating element types.