title: An online method for the analysis of volatile organic compounds in electronic cigarette aerosol based on proton transfer reaction mass spectrometry.
abstract: BACKGROUND
  Due to the recent rapid increase in electronic cigarette (e-cigarette) use worldwide, there is a strong scientific but also practical interest in analyzing e-cigarette aerosols. Most studies to date have used standardized but time-consuming offline technologies. Here a proof-of-concept for a fast online quantification setup based on proton transfer reaction mass spectrometry (PTR-MS) is presented.
  
  
  METHODS
  The combination of a novel sampling interface with a time-of-flight PTR-MS instrument specially designed for three scenarios is introduced: (i) mainstream aerosol analysis (aerosol that the user inhales prior to exhalation), and analysis of exhaled breath following (ii) mouth-hold (no inhalation) and (iii) inhalation of e-cigarette aerosols. A double-stage dilution setup allows the various concentration ranges in these scenarios to be accessed.
  
  
  RESULTS
  First, the instrument is calibrated for the three principal constituents of the e-cigarettes' liquids, namely propylene glycol, vegetable glycerol and nicotine. With the double-stage dilution the instrument's dynamic range was easily adapted to cover the concentration ranges obtained in the three scenarios: 20-1100 ppmv for the mainstream aerosol characterisation; 4-300 ppmv for the mouth-hold; and 2 ppbv to 20 ppmv for the inhalation experiment.
  
  
  CONCLUSIONS
  It is demonstrated that the novel setup enables fast, high time resolution e-cigarette studies with online quantification. This enables the analysis and understanding of any puff-by-puff variations in e-cigarette aerosols. Large-scale studies involving a high number of volunteers will benefit from considerably higher sample throughput and shorter data processing times.
authors: IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020, Innsbruck, Austria.
authors: Kostiantyn
authors: K
authors: Breiev
authors: Fontem Ventures B.V., Barbara Strozzilaan 101, 1083 HN, Amsterdam, The Netherlands.
authors: Kerstin M M
authors: KM
authors: Burseg
authors: Fontem Ventures B.V., Barbara Strozzilaan 101, 1083 HN, Amsterdam, The Netherlands.
authors: Grant
authors: G
authors: O'Connell
authors: IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020, Innsbruck, Austria.
authors: Eugen
authors: E
authors: Hartungen
authors: Fontem Ventures B.V., Barbara Strozzilaan 101, 1083 HN, Amsterdam, The Netherlands.
authors: Stefan S
authors: SS
authors: Biel
authors: SEITA - Imperial Tobacco Group, 48 rue Danton, 45404, Fleury-les-Aubrais, France.
authors: Xavier
authors: X
authors: Cahours
authors: SEITA - Imperial Tobacco Group, 48 rue Danton, 45404, Fleury-les-Aubrais, France.
authors: Stéphane
authors: S
authors: Colard
authors: IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020, Innsbruck, Austria.|Institut für Ionenphysik und Angewandte Physik, Leopold-Franzens Universität Innsbruck, Technikerstrasse 25/3, 6020, Innsbruck, Austria.
authors: Tilmann D
authors: TD
authors: Märk
authors: IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020, Innsbruck, Austria.
authors: Philipp
authors: P
authors: Sulzer