title: Nicotine levels and presence of selected tobacco-derived toxins in tobacco flavoured electronic cigarette refill liquids.
abstract: BACKGROUND
  Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids.
  
  
  METHODS
  Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products.
  
  
  RESULTS
  Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from -21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200-300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products.
  
  
  CONCLUSIONS
  NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2-3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products.
authors: Department of Cardiology, Onassis Cardiac Surgery Center, Kallithea 17674, Greece. kfarsalinos@gmail.com.|Department of Pharmacy, University of Patras, Rio 26500, Greece. kfarsalinos@gmail.com.
authors: Konstantinos E
authors: KE
authors: Farsalinos
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. Gene.Gillman@enthalpy.com.
authors: I Gene
authors: IG
authors: Gillman
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. MMelvin@lortobco.com.
authors: Matt S
authors: MS
authors: Melvin
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. Amelia.Paolantonio@enthalpy.com.
authors: Amelia R
authors: AR
authors: Paolantonio
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. Wendy.Gardow@enthalpy.com.
authors: Wendy J
authors: WJ
authors: Gardow
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. Kathy.Humphries@enthalpy.com.
authors: Kathy E
authors: KE
authors: Humphries
authors: Enthalpy Analytical Inc., Durham NC 27713, USA. Sherri.Brown@enthalpy.com.
authors: Sherri E
authors: SE
authors: Brown
authors: Department of Pharmacy, University of Patras, Rio 26500, Greece. kpoulas@otenet.gr.
authors: Konstantinos
authors: K
authors: Poulas
authors: Department of Cardiology, Onassis Cardiac Surgery Center, Kallithea 17674, Greece. vvoudris@otenet.gr.
authors: Vassilis
authors: V
authors: Voudris
mesh_terms: D000079:Acetaldehyde / Q000032:analysis; D066300:Electronic Nicotine Delivery Systems; D005557:Formaldehyde / Q000032:analysis; D009538:Nicotine / Q000032:analysis*; D009566:Nitrates / Q000032:analysis; D009602:Nitrosamines / Q000032:analysis; D010636:Phenols / Q000032:analysis; D010936:Plant Extracts / Q000032:analysis*; D014026:Nicotiana / Q000737:chemistry* / Q000633:toxicity
chemical_list: D009566:Nitrates; D009602:Nitrosamines; D010636:Phenols; D010936:Plant Extracts; D005557:Formaldehyde; D009538:Nicotine; D000079:Acetaldehyde