A method to measure total gaseous fluorine
Bibliographic record
Abstract
Total fluorine (TF) analysis is a powerful tool for the characterization of organofluorine contaminants in the environment. Organofluorine compounds are known primarily with respect to the notorious subgroup of poly- and perfluoroalkyl substances (PFAS) and as potent greenhouse gases that can impact climate. The use of targeted methods for every organofluorine compound in the environment is not feasible. While methods are available for TF analysis of condensed phase samples, no technique exists for gas phase TF measurements (TFg). Herein we demonstrate an in-situ instrumental method for TFg via platinum catalyzed thermolysis at 1000 °C in the presence of propane. TFg is fully converted into HF and subsequently quan-tified by existing techniques for F-. The method was validated using nine organofluorine compounds with differing functional groups. We characterized TFg and compared to common speciated measurements in the headspace of four commercial fluorosurfactants and outdoor air. Most TFg (65%-99.8%) in the fluoro-surfactant headspace was unknown. In outdoor air, >50% of TFg was unknown. These high quantities of unknown organofluorine indicate a measurement gap in the gas phase, which could have important impli-cations for atmospheric sources and burdens of PFAS and fluorinated greenhouse gases.
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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 | 0.023 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.008 |
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; both teacher heads agree on what is shown here.
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".