Disposable electronic cigarettes: Chemical composition in new and used devices

Disposable electronic cigarettes (ECs), also commonly known as vapes, have gained increasing popularity, particularly among young users, due to their accessibility and variety of flavours. Although the constituents of refill- able tank-style and cartridge-based EC devices have been studied, only a limited amount of data is currently avail- able for disposable or single-use ECs. In this study, the chemicals of 60 disposable ECs have been investigated, including different flavours and brands. Ethyl maltol and benzoic acid were quantified across various e-liquid flavours, brands and nicotine concentrations from disposable ECs. The chemical composition changes with EC usage were also investigated, comparing new and used disposable ECs. Headspace gas chromatography/mass spectrometry was employed to identify and quantify the chemicals. 89 % of the analysed EC liquids presented ethyl maltol, where 42 % of them presents 10 times higher concentrations than the ones set by the General Standard for Food Additives and 88 % of them exceed the concentration previously reported as cytotoxic. 87 % of the investigated EC fluids contained benzoic acid, where 71 % of them exceeded 20 times the values reported as genotoxic in human lymphocytes. Our results support the link between benzoic acid and nicotine contain and provide new information regarding the concentration changes within flavours and suppliers. Both chemicals have shown similar patterns through usage, presenting an increase of concentration between 40 and 80 puff. Our study demonstrates the need of maintaining constant oversight of e-liquids, as they are continuously changing in often subtle but toxicologically detrimental ways.