Quantitative determination of selected carbonyls in tobacco, tobacco materials, e-liquids and emissions of conventional cigarettes and novel tobacco products (NTPs)
Background/aims: Carbonyls play an important role in the toxicological assessment of tobacco and nicotine containing products. Four commercially available tobacco and nicotine containing products (Conventional Cigarette/CC, E cigarette/EC and two Heat-not-Burn Tobacco products/HnBT1 and HnBT2) were analysed with respect to the occurrence of eight carbonyls (formaldehyde, acetaldehyde, acetone, acrolein, propylaldehyde, crotonaldehyde, 2-butanone, butaldehyde).
Methods: The concentrations of the respective carbonyls were determined by HPLC/UV in tobacco, tobacco materials, e liquids and emissions, i.e. mainstream smoke/aerosol and gas phase sampled in phosphate buffered saline (PBS) solution (as used for in vitro testing). Emissions generation was done with a linear smoking/puffing machine and carbonyls were trapped on a dinitrophenylhydrazine (DPNH) pre-treated Cambridge Filter Pad (CFP) as well as in impingers containing a PBS solution with DNPH.
Results: Six carbonyls were found in the CC, two in the e liquid and four on two HnBT sticks. The CC exhibited the highest levels of all investigated materials. In the mainstream smoke/aerosol of the CC, 2 to 1,000 times higher carbonyl concentrations compared to the other three NTPs were measured. All eight carbonyls were determined in the smoke of the CC, whilst for the other three NTPs only six or five carbonyls were found. Quantitative analysis showed that for all four products, the major amount of carbonyls were formed during burning/heating (~90 %). The ratio of carbonyls trapped into PBS was between 0 % and 83 % and dependent from the analyte as well as product.
Conclusion: All three NTP materials exhibited lower levels of carbonyls compared to the CC. The concentration of carbonyls in the emissions of the CC were by far the highest of all products. This indicates that even for NTPs, carbonyls might not only be released from the material by a simple distillation process, but also formed during product usage.