LC-MS/MS analysis of components in smoke from e-cigarettes that use guarana extract as the caffeine source.

Currently, e-cigarette products to inhale caffeine (Caf) are commercially available and widely used. Guarana extract (GE) is used as the caffeine source in some e-cigarette products. In this study, an LC-MS/MS analysis of components in the smoke from e-cigarettes with GE was performed. The concentration ranges of Caf and the minor components theophylline (TP), theobromine (TB), and paraxanthine (PX) in e-liquid and cigarette smoke extract (CSE) of five e-cigarette products were determined. The concentration ranges of e-liquid and CSE were 2.17-8.62 mg/mL and 0.17-1.17 µg/puff for Caf, 0.09-37.58 µg/mL and 0.03-11.88 ng/puff for TB, 50.28-185.26 ng/mL and 0.00-0.05 ng/puff for TP, and 0.44-4.09 µg/mL and 0.03-0.20 ng/puff for PX, respectively. By comparing the peak area ratios of e-liquid and CSE, we clarified that the heat degradation of Caf to its related components in GE products was accelerated. Epicatechin, which is another typical component in GE, was determined for CSE, but not for e-liquid.

Analysis of vaporized caffeine in smoke from e-cigarettes using liquid chromatography-tandem mass spectrometry and clarification of minor components.

PURPOSE: Electronic cigarettes (e-cigarettes) are used widely, and e-cigarettes containing caffeine (Caf) have recently become commercially available. However, no risk evaluation of these Caf-containing products has been performed to date. Such an evaluation requires a sensitive analytical method for quantifying Caf in smoke from e-cigarettes. The aim of this study was to establish a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying vaporized Caf from commercially available e-cigarettes, and to determine minor components related to Caf in cigarette smoke extract (CSE). METHODS: A sampling system for Caf using a suction pump was designed and sampling conditions were optimized. RESULTS: The optimized LC-MS/MS conditions allowed the sensitive determination of Caf in smoke with a limit of detection of 0.03 ng/mL at a signal-to-noise ratio of 3. The method was applied to CSEs from five e-cigarette products and the concentration of Caf ranged from 0.894 ± 0.090 to 3.32 ± 0.14 µg/mL smoke (n = 3). Additionally, minor components related to Caf, such as theobromine, theophylline, and paraxanthine, were detected in CSE and in e-liquid at very low concentrations, indicating that they were impurities in e-liquid and vaporized along with Caf. CONCLUSION: This is the first report to determine the concentration of vaporized Caf using an LC-MS/MS method and to clarify several minor components in smoke from e-cigarettes.