Heated tobacco products (HTPs), whatever their design, deliver reduced harmful and potentially harmful constituents (HPHCs) aerosol emissions thanks to reduced temperature applied to tobacco. Last year we presented a mass balance method (2020_ST06) to figure out the water, glycerol and nicotine contents from the tobacco to the aerosol. We have complemented the method with the addition of tobacco specific nitrosamines (TSNAs) to the mass balance methodology.

The objectives of this study were to adjust the TSNA analytical method to the HTPs range and to assess the feasibility of a TSNA mass balance to understand the influence of the device and stick designs on aerosol TSNAs.

Modified Health Canada Intense puffing regime was used to generate aerosol on a linear smoking machine. A procedure for sample collection before and after heating was developed with some adjustments in order to have TSNA levels above quantification limits.

The following steps were added:

• total NNK (free and bound) quantification after sample autoclaving, measured in tobacco before heating and after heating,
• removal of binding agents in TSNA aliquot by precipitation before analysis to limit troubleshooting on the high pressure liquid chromatography system.

A control commercial HTP stick stored in a freezer was analyzed at the beginning and at the end of each puffing session to control and ensure the stability of the puffing and analytical system. The coefficient of variation of TSNAs is below 10 %.

This mass balance approach allows the actual TSNA transfer rate and the TSNA retention in cooling and filtering segments, which vary across different HTPs systems, to be defined.