Tobacco-Specific Nitrosamines in the Tobacco and Mainstream Smoke of Commercial Little Cigars

• Published in: Chemical research in toxicology 2021-04, Vol.34 (4), p.1034-1045
• Main Authors: Edwards, Selvin H, Hassink, Matthew D, Taylor, Kenneth M, Watson, Clifford H, Kuklenyik, Peter, Kimbrell, Brett, Wang, Liqun, Chen, Patrick, Valentín-Blasini, Liza
• Format: Article
• Language: English
• Subjects: Nitrosamines - analysis; Smoke - analysis; Tobacco Products - analysis
• ISSN: 0893-228X; 1520-5010; 1520-5010
• DOI: 10.1021/acs.chemrestox.0c00367

Cigars are among the broad variety of tobacco products that have not been as extensively studied and characterized as cigarettes. Small cigars wrapped in a tobacco-containing sheet, commonly referred to as little cigars, are a subcategory that are similar to conventional cigarettes with respect to dimensions, filters, and overall appearance. Tobacco-specific nitrosamines (TSNAs) are carcinogens in the tobacco used in both little cigars and cigarettes. This study uses a validated high-performance liquid chromatography–electrospray tandem mass spectrometry (LC–MS/MS) method to measure the TSNAs 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N′-nitrosonornicotine (NNN) in the tobacco filler and the nonintense International Organization for Standardization smoking regimen, ISO 3308, and the newer ISO 20778 Cigarette Intensive (CI) smoking regimen mainstream smoke of 60 commercial little cigars. Tobacco filler NNK and NNN quantities ranged from 26 to 2950 and 1440 to 12 100 ng/g tobacco, respectively. NNK and NNN by the ISO nonintense smoking regimen ranged from 89 to 879 and 200 to 1540 ng/cigar, respectively; by the CI regimen, NNK and NNN ranged from 138 to 1570 and 445 to 2780 ng/cigar, respectively. The average transfer (%) for NNK and NNN from tobacco filler to mainstream smoke was 24% and 36% by the ISO nonintense and CI smoking regimens, respectively. By the ISO nonintense and CI smoking regimens, mainstream smoke NNK and NNN yields showed a moderate to strong correlation (ISO nonintense, R 2 = 0.60–0.68, p < 0.0001; CI, R 2 = 0.78–0.81, p < 0.0001) with tobacco filler NNK and NNN quantities. In addition, the mainstream smoke NNK and NNN yields of little cigars were determined to be 3- to 5-fold higher compared to previously tested commercial cigarettes. The mainstream smoke NNK and NNN yields have wide variation among commercial little cigars and suggest that, despite design similarities to cigarettes, machine-smoke yields of carcinogenic TSNAs are higher in little cigars.