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.

Nicotine-related impurities in e-cigarette cartridges and refill e-liquids

“…[17,18] An earlier study by Trehy et al [9] observed that nicotine content labeling issues were also present with most of the products they tested. While some studies have reported nicotine levels higher than label claims (e.g., Trehy et al [9] and Farsalinos et al [19] ), consistent with Lisko et al, [6] for the samples measured in this study, all nicotine values were lower than reported values. Laugesen et al [20] also observed differences between labeled and measured nicotine concentration, and they concluded that these differences were due to a "lack of quality control."…”

“…Nicotine levels were also evaluated in the commercial products to confirm label claims and, consistent with previously published results, inconsistencies were observed for some products. [6,9,18,19,21,22] Most products were within 30% of the label claim, while others exceeded 50%. Using the targeted method described herein using MS with MRM, it was possible to achieve the sensitivity necessary to detect most of the nicotine-related impurities in all the commercial products tested.…”

Adolescents’ and Young Adults’ Knowledge and Beliefs About Constituents in Novel Tobacco Products

“…We selected these constituents because they have been found to be present in novel tobacco products. [4][5][6][7][8] Participants were shown a list of these constituents and asked whether they had heard of or knew anything about each constituent. Participants were also asked what they would like to know about these constituents.…”

“…Since the focus groups were conducted, new research has continued to expand the list of constituents found in novel tobacco products and their smoke or aerosol, especially for e-cigarettes. 4,5…”

“…2,3 While this list applies only to currently regulated tobacco products, including cigarettes and cigarette smoke, smokeless tobacco, and roll-your-own tobacco, many of the constituents on the reduced list are also known to be in novel tobacco products and their smoke or aerosol, such as arsenic, carbon monoxide, and formaldehyde. [4][5][6][7][8] Some novel tobacco products and their smoke, like little cigars, cigarillos, and hookah, often contain similar levels of constituents as cigarettes. [4][5][6][7][8] While e-cigarettes and e-cigarette aerosol generally contain lower levels of and fewer constituents than other tobacco products, 4,5 the effects of repeated, long-term exposure to low levels of many constituents are still unknown.…”