Integration of Time and Spatially Resolved In-Situ Temperature and Pressure Measurements With Soft Ionisation Mass Spectrometry Inside Burning Superslim and King-Size Cigarettes

Abstract

SummaryBackground: Combustion as well as pyrolysis of tobacco greatly affect the type and levels of toxicants in cigarette smoke. We previously developed an approach to combine simultaneous temperature and pressure measurements with fast in-situ microprobe chemical sampling inside a burning cigarette, producing a series of temperature and gas-flow velocity maps that characterize this dynamic system in response to externally applied air flow.Aim: Two cigarette types differing only in diameter were puffed under ISO 3308 and Health Canada Intense (HCI) regimes to further understand the dynamic interaction of air flow and cigarette design parameters on tobacco combustion and pyrolysis by applying the thermophysical and thermo-chemical mapping approach.Methods: Three types of sampling probes were inserted, which are thermocouple arrays for gas-phase temperature, quartz tubes for pressure measurement, and a heated sampling microprobe coupled to a single-photon soft ionisation mass spectrometer for chemical analysis. Two kinds of similarly constructed cigarettes with the same blend were analysed: superslim (17 mm circumference) and king-size (24 mm circumference).Synchronization among the sampled signals was achieved by mapping two probes (e.g., temperature/chemistry or temperature/pressure) at a time. The physical and chemical events were visualised and compared between the cigarettes and puffing regimes.Results: A series of temperature, pressure, and chemical maps were obtained for the superslim and king-size cigarettes under ISO and HCI conditions. The pressure in the burning cigarette was higher in the superslim cigarette, and the temperature distribution differed between the two cigarette formats. As expected, temperatures and pressures were higher under HCI puffing than under ISO puffing for both cigarette formats. Thermochemical maps for e.g., benzene and nitric oxide formation were qualitatively similar between the superslim and king-size cigarettes. For other substances the distribution was markedly different.Conclusion: The application of multi-probe in-situ chemical sampling is suitable to analyse highly dynamic combustion and pyrolysis processes occurring inside the two types of cigarettes. Ultimately, a direct comparison of cigarette circumferences on the complex combustion processes and formation of smoke constituents was achieved. [Beitr. Tabakforsch. Int. 29 (2020) 44–54]

Aerosol Formation and Transfer in Open- and Closed-Ended Heated Tobacco Products

“…LI et al used fine thermocouples to measure the gas-phase temperature and its distribution inside the burning cone during puffing (9)(10)(11), which mimicked one of the most important studies for characterizing the combustion behavior of a cigarette conducted by BAKER and others (1-3). In addition to show that the gas-phase temperature and its distribution within a burning cone is a key parameter reflecting the heat and mass transfer processes (12)(13)(14)(15), these researchers also extended this approach to include fine pressure probes to measure in-situ pressure variations during the puffing (16)(17). Their reconstructed 2D gas flow maps in and around the burning cone showed an increase in the draw resistance towards the front of the burning cone, accompanied by the changed airflow pathway and air flow velocity during a 2-s bell-shaped puff.…”