Commercially available tobacco heating products (THPs) are somehow hybrids between conventional cigarettes and e-cigarettes, as tobacco material is not burnt, but heated. Although the first THPs were coal heated and launched decades ago, currently available THPs are working mainly electrically.

Vacuum photoionisation (PI) is a reliable tool performing on-line, puff resolved analysis of smoking products. However, SPI (Single-Photon-Ionization) ionises a wide range of organic molecules and REMPI (Resonance-Enhanced-Multi-Photon-Ionization) focuses primarily on aromatic structures. Adapting the used REMPI wavelength supports spectroscopic approaches for analysis and can also allow the separation of isobaric compounds. Especially the comprehensive use of SPI and REMPI with several wavelengths enables a sophisticated analytical view into the release mechanism of a smoking product.

Within this study two commercially available THP devices were compared using 118 nm SPI as well as 248 nm and 266 nm REMPI. The devices show significant differences in puffing duration, total vapour amount and puff-by-puff nicotine release. Furthermore, the release dynamics and composition of other compounds and HPHCs (Harmful or potentially harmful compounds) varies between both devices. Furthermore, the puff-by-puff release profiles are highly related to the heating/temperature programme used in the THP devices. One device seems to exhibit an additional heating impulse for the second half of the puffs. Even if the substance release spectrum is more pronounced, the main organic compounds being released are glycerol and nicotine. All other compounds appear at a much lower concentration level. Although the absolute amount of individual compounds in aerosol are significantly different between both THPs, the results change if individual compound concentrations are normalized to total amount of gas phase/vapour or total amount of nicotine as reference values.

Overall, photoionisation MS, especially if SPI and REMPI is combined, is a well-suited tool for the investigation of THPs and other smoking/puffing products on a puff by puff on-line basis.