Non-targeted analysis of the particulate phase of heated tobacco product aerosol and cigarette mainstream tobacco smoke by thermal desorption comprehensive two-dimensional gas chromatography with dual flame ionisation and mass spectrometric detection.

An analytical methodology based on thermal desorption and comprehensive two-dimensional gas chromatography with dual time-of-flight mass spectrometry and flame ionization detection (TD-GC × GC-TOFMS/FID) has been developed for non-target analysis of volatile organic compounds (VOCs). The technique was optimised for the measurement of the VOC content of the particulate phase (PP) fraction of aerosols produced by a tobacco heating product (THP1.0) and 3R4F mainstream tobacco smoke (MTS). The method involves sampling the PP fraction on quartz wool packed in a sorbent tube directly connected to machine-puffing, followed by a dilution through a TD recollection procedure over Tenax/Sulficarb sorbent before TD-GC × GC-TOFMS/FID analysis. The comparison of the VOC content of the PP fraction of aerosols produced by THP1.0 and MTS highlighted the compositional difference between tobacco combustion (592 peaks) and tobacco heating process (160 peaks). Mass spectrometric signals were used for qualitative analyses based on linear retention indices, mass spectral matches, and GC × GC structured chromatograms, which collectively identified up to 90% of analytes detected in PP samples. FID signals were used for semi-quantitative analyses based on a chemical class external calibration method. The global chemical composition of PP samples showed that hydrocarbons, oxygenated, and nitrogen-containing compounds were fewer in number and much less abundant in THP1.0 PP. Overall, 93 compounds were common to the two sample types. Excepted for a few highly volatile compounds (mainly furan family) as well as glycerine and its acetate, analyte concentrations were higher in MTS PP.

Comprehensive comparative compositional study of the vapour phase of cigarette mainstream tobacco smoke and tobacco heating product aerosol.

A simple direct sample collection/dilution and introduction method was developed using quartz wool and Tenax/sulficarb sorbents for thermal desorption and comprehensive two-dimensional gas chromatography (TD-GC × GC) analyses of volatile organic compounds from vapour phase (VP) fractions of aerosol produced by tobacco heating products (THP1.0) and 3R4F mainstream tobacco smoke (MTS). Analyses were carried out using flame ionisation detection (FID) for semi-quantification and both low and high resolution time-of-flight mass spectrometry (LR/HR-TOFMS) for qualitative comparison and peak assignment. Qualitative analysis was carried out by combining identification data based on linear retention indices (LRIs) with a match window of ±10 index units, mass spectral forward and reverse library searches (from LR and HRTOFMS spectra) with a match factor threshold of >700 (both forward and reverse), and accurate mass values of ± 3 ppm for increased confidence in peak identification. Using this comprehensive approach of data mining, a total of 79 out of 85 compounds and a total of 198 out of 202 compounds were identified in THP1.0 aerosol and in 3R4F MTS, respectively. Among the identified analytes, a set of 35 compounds was found in both VP sample types. Semi-quantitative analyses were carried out using a chemical class-based external calibration method. Acyclic, alicyclic, aromatic hydrocarbons and ketones appeared to be prominent in 3R4F MTS VP, whereas larger amounts of aldehydes, ketones, heterocyclic hydrocarbons and esters were present in THP1.0 aerosol VP. The results demontsrate the capability and versatility of the method for the characterization and comparison of complex aerosol samples and highlighted the relative chemical simplicity of THP1.0 aerosol in comparison to MTS.