Open Characterization of Vaping Liquids in Canada: Chemical Profiles and Trends

Abstract

Currently, there is a lack of comprehensive data on the diversity of chemicals present in vaping liquids. To address this gap, a non-targeted analysis of 825 vaping liquids collected between 2017 and 2019 from Canadian retailers was conducted. Prior to mass spectrometry analysis, samples were diluted 1:500 v/v with methanol or acetonitrile. Chemical compound separation and analysis was carried out using gas chromatography and triple quadrupole mass spectrometry (GC-MS/MS) systems operated in the full scan mode and mass range of 35–450 m/z. Mass spectrum for each sample was obtained in electron ionization at 70 eV and processed. Non-targeted identification workflow included use of automated mass spectral deconvolution and identification system (AMDIS), where required, as well as a number of commercially available spectral libraries. In order to validate identities, an in-house database of expected compounds previously detected in vaping liquids was used along with genuine analytical standards for compounds of interest. This resulted in a dataset of over 1,500 unique detected chemicals. Approximately half of these chemical compounds were detected only once in a single product and not in multiple products analyzed. For any sample analyzed, on average, 40% of the chemical constituents appeared to have flavouring properties. The remainder were nicotine and related alkaloids, processing, degradation or indirect additives, natural extractives and compounds with unknown roles. Data published here from the project on the Open Characterization of vaping liquids is unique as it offers a detailed understanding of products’ flavour chemical profiles, the presence and frequency of chemicals of potential health concern, as well as trends and changes in products’ chemical complexity over a three-year period. Non-targeted chemical surveillance such as this present valuable tools to public health officials and researchers in responding to emergent issues such as vaping associated lung injury or informing chemical based strategies which may be aimed at addressing product safety or appeal.

Reducing attractiveness of e-liquids: proposal for a restrictive list of tobacco-related flavourings

“…Non-targeted screening methods can maximise the chance of detection. Because most flavourings are volatile, gas chromatography coupled to mass spectrometry is a common and suitable technique for flavour analysis that has previously been used for e-liquids 17 37 38. Mass spectra can also provide information about the identity of unknown (non-allowed) flavourings.…”

“…For example, the Dutch list is overall stricter in that it only allows tobacco-flavoured e-liquids, whereas the Canadian list also allows mint/menthol-flavoured e-liquids. Additionally, Health Canada based their list on analytical chemical measurements in 825 e-liquids 17 obtained from the Canadian market, whereas we based our list on data provided by manufacturers through the EU-CEG system for all e-liquids notified for the Dutch market. Moreover, both institutes did not use exactly the same inclusion and exclusion criteria; for example, we excluded substances with health risks.…”

“…Only 16% of these e-liquids had a tobacco flavour; most e-liquids had sweet or fruity flavours 15. To impart such flavours, manufacturers mainly add flavourings with a sweet, fruity flavour to e-liquids (such as vanillin, ethyl maltol and ethyl butyrate16 17).…”

Quantitation and Stability of Nicotine in Canadian Vaping Liquids

“…The procedure for non-targeted analysis has been previously described [21]. In summary, samples were characterized using the gas chromatogram tandem mass spectrometer operated in a full scan mode.…”

Crystallization and Solvent Evaporation Ionization Mass Spectrometry (CSEI-MS) for Rapid Detection of Drugs in Complex Matrices

“…Developing rapid and reliable analytical methods for trace chemical components residing in the environment is of significance due to the potential risks for public health. − This is not an easy task as these components are often diverse and have low contents in a complex matrices environment. Among them, antibiotics and antimicrobials are widely used in daily life.…”