Analysis of Nicotine Alkaloids and Impurities in Liquids for e-Cigarettes by LC-MS, GC-MS, and ICP-MS.

The purpose of this study was the development of various analytical mass spectrometry (MS) methods to investigate the chemical composition of e-liquids used in electronic cigarettes and characterize their quality. Low-quality nicotine (the main active compound), glycerol, propylene glycol (solvents), or flavors could greatly increase the toxicity. The search of alkaloid contaminants of nicotine was performed by liquid chromatography-tandem mass spectrometry (LC-MS-MS) after a study of fragmentation pathways by high-resolution electrospray ionization (ESI)-MS. A fully validated method for quantitation of organic polar impurities such as cotinine, anabasine, myosmine, nornicotine, and N-nitroso-nornicotine and nicotine itself was developed using MS coupled to ultrahigh-pressure liquid chromatography (UHPLC). To evaluate organic volatile toxicants, the headspace from e-cigarette refill liquids was sampled by the purge-and-trap method to perform gas chromatography (GC)-MS analysis. Finally, heavy metal residues as inorganic toxicants were determined by inductively coupled plasma (ICP)-MS after simple dilution. A number of cases of contamination by metals (mainly arsenic) were detected. [ABSTRACT FROM AUTHOR]