Chemical Analysis and Flavour Distribution of Electronic Cigarettes in Australian Schools.

Introduction: Adolescent usage of electronic cigarettes has increased globally. Inconsistent, or absent, labelling of nicotine and other ingredients requires chemical analysis to accurately determine the chemical composition of these products.

Methods: Electronic cigarettes confiscated from public and private high school students (N=598) were provided for analysis from three regions in New South Wales, Australia. The products were examined for brand, model and flavour and a subset were further analysed for chemical composition (n=410) quantifying nicotine, synthetic cooling agents, flavouring chemicals and prohibited ingredients by gas chromatography-mass spectrometry (GC-MS).

Results: The majority of samples provided were fruity-flavoured disposable e-cigarettes across three main brands (IGET, HQD and Gunnpod). Nicotine was quantified in 97.3% of disposable samples with an average concentration of 40.0 mg/mL while one refill e-liquid was found to contain nicotine at a low concentration. Almost all samples contained the coolant WS-23 in relatively high concentrations compared to other flavouring chemicals present. Chemicals prohibited under the TGO110 (Australian e-cigarette product standard) were identified in 3.4% of the samples which were chemically analysed. This included the presence of ethylene glycol in moderately high concentrations (up to 13.2 mg/mL).

Conclusions: Australian students' preferences for fruity, disposable e-cigarettes were identified regardless of region with the vast majority containing high concentrations of nicotine. WS-23 was found in most disposable e-cigarettes, potentially to reduce the throat irritation from nicotine and other flavouring chemicals. The inhalational safety of the samples is of concern due to health risks associated with detected prohibited compounds, particularly ethylene glycol.

Implications: This is the first study to quantify nicotine, coolants and flavouring chemicals in ecigarette products seized from Australian high school students and has significant implications for future policy development. Students appear to be almost exclusively using disposable ecigarettes with high nicotine concentrations and predominately fruity flavours. WS-23 may potentially be added to disposable e-cigarettes to facilitate the uptake of these products by adolescents unaccustomed to the throat irritation from nicotine and intense flavours. The ecigarette coils were found to have degraded over time, potentially affecting the composition of the aerosol and leaching of metals.