In a single puff, this “non-targeted” method can detect and identify volatile and semi-volatile substances present at levels suitable for toxicological risk assessment.
Although studies indicate that e-cigarettes have the potential to be less risky compared to combustible tobacco cigarettes, it remains important to develop capabilities to identify potentially hazardous substances that may be present in e-cigarette vapour. Typically, the methods used to determine vapour composition are aimed at detecting specific classes of compounds, and these methods have not been designed to detect and identify unpredicted substances. And those methods that can are usually not sensitive enough to enable meaningful toxicity assessment.
Using thermal desorption - gas chromatography – time-of-flight mass spectrometry (TD–GC–TOFMS), we have developed a technique that is sensitive enough to detect unforeseen volatile and semi-volatile substances in e-cigarette vapour. Importantly, this is done from a single, 3-second puff and at 5ng/puff or more, a sensitivity BAT toxicologists have identified as best practice for risk assessing tobacco and nicotine products.¹ Moreover, the method incorporates a robust quality control process to distinguish possible chemical artefacts formed during analysis.
Evaluating its practicality, scientists at British American Tobacco showed the method could be used to screen vapour from three different commercial products (Vype e-Stick (cig-a-like), Vype ePen (closed modular), and Nhoss Lounge (open tank modular)), and three test liquids. They were also able to use the technique to distinguish vapours from different eliquid flavours used in Vype ePen (mint, tobacco, cherry and unflavoured).The technique can only detect those volatile and semi-volatile substances compatible with GC–MS. Nevertheless, “Although it does not provide the whole picture, our method provides an important piece of the puzzle and addresses a potential knowledge gap in e-cigarette safety assessments,” says Chris Wright, Head of Analytical Science at British American Tobacco. “When developing novel products there are potential unknowns. By detecting compounds at the very low levels relevant for product risk assessment, this technique helps identify potential chemical hazards and is best available practice with this technology.”
1. S. Costigan and C. Meredith. An approach to ingredient screening and toxicological risk assessment of flavours in e-liquids. Regul Toxicol Pharmacol 72 (2):361-369, 2015.