A new method for the analysis of carbonyl compounds in e-cigarette liquids
Carbonyl compounds (carbonyls) are organic molecules that contain a carbon atom double-bonded to an oxygen atom. Specifically these include compounds known as aldehydes and ketones that are usually found in traditional mainstream tobacco smoke and are of interest to many regulatory bodies including the United States Food and Drug Administration (FDA), Health Canada and ANVISA (Brazil). The increasing popularity of e-cigarette and vapor products carries with it an increasing interest in the measurement of many of the Harmful and Potentially Harmful Constituents (HPHCs) identified by the FDA.
E-cigarettes and electronic vapor products typically contain a nicotine solution (e-liquid) with high levels of vegetable glycerin (VG) or propylene glycol (PG) that can potentially decompose into various carbonyl compounds at high temperatures. Due to the wide concentration ranges of carbonyls likely to be observed in e-cigarettes and electronic vapor products, the standard tobacco emissions carbonyl assay using 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by HPLC separation may not provide the sensitivity and specificity needed for this analysis.
The purpose of this presentation is to demonstrate a new analytical method for testing carbonyl compounds from e-liquids. The sample is dissolved in acetonitrile, derivatized with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA), then extracted with hexane. The hexane extract is analyzed by single quadruple gas chromatography-mass spectrometry (GC/MS) using negative chemical ionization.
The validated method works for a wide range of carbonyl containing compounds and provides ng/g detection with good specificity, robustness and reproducibility. The potential application of the method to analysis of carbonyls in e-cigarette vapor will also be discussed.