Investigation of emissions from heated tobacco with comprehensive two-dimensional gas chromatography with mass spectrometry detection
Bibliographic record
Abstract
Cigarette smoke is a highly complex dynamic aerosol system generated by distillation, pyrolysis and combustion reactions when the tobacco is burnt. As the burning tip of a cigarette reaches temperatures of up to 1000oC, more than 6800 compounds have been identified in mainstream smoke. Heating tobacco to temperatures lower than 300oC and limiting the range of chemical reaction to distillation processes simplifies the composition of emissions. The aim of the present study is to investigate THP complexity, focusing on particulate phase (PP), by means of comprehensive two-dimensional gas chromatography (GC×GC) coupled to time-of-flight mass spectrometry (TOFMS). A headspace solid-phase micro extraction (HS-SPME) method has been optimized by means of design of experiment (DoE) in terms of most efficient extraction of PP constituents of THP. Emissions from heated tobacco were generated using an A14 smoking engine (Borgwaldt, Germany) according to the Health Canada Intense regime (method T-115, Health Canada) applying 12 bell shaped puffs of 55ml volume, 2s puff duration and 30s interval between the puffs. The particulate phase of smoke was collected on a standard Cambridge filter pads for head space solid-phase micro extraction (HS-SPME) analysis. Different SPME fibres including 85 μm polyacrylate, 50/30 μm divinylbenzene/carboxen/polydimethylsiloxane, 85 μm carboxen/polydimethylsiloxane, 65μm polydimethylsiloxane/divinylbenzene and 100 μm polydimethylsiloxane were evaluated. The GC×GC-TOFMS system consisted of an Agilent 7890GC with Gerstel MPS2 (equipped in SPME and CIS4) and a Pegasus 4D with quad jet thermal modulator and secondary oven. The column set comprised RTX-5MS (30m x 0.25 mm ID x 0.25μm df) and Rxi17Sil MS (1.0m x 0.15 mm ID x 0.15μm df) from Restek. LECO ChromaTOF® software (4.50) was used for data acquisition. GC ImageTM software package (2.5b6) was used for GCxGC data processing. For design of experiments The Unscrambler X 10.3 was used. For the most abundant compounds, MS data and LRIs of each blob were compared to MS and LRI libraries (NIST14, AromaOffice 2D) for tentative identification. Amongst the 200 compounds tentatively identified, 68% were previously reported as constituents of tobacco leaves and 73% were either flavour and fragrance agents or natural substances and extractives.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".