Quantification of Nitryl Chloride at Part Per Trillion Mixing Ratios by Thermal Dissociation Cavity Ring-Down Spectroscopy
Bibliographic record
Abstract
Nitryl chloride (ClNO(2)) is an important nocturnal nitrogen oxide reservoir species in the troposphere. Here, we report a novel method, thermal dissociation cavity ring-down spectroscopy (TD-CRDS), to quantify ClNO(2) mixing ratios with tens of parts-per-trillion by volume (pptv) sensitivity. The mixing ratios of ClNO(2) are determined by blue diode laser CRDS of NO(2), produced from quantitative thermal dissociation of ClNO(2) in an inlet heated to 450 °C, relative to NO(2) observed in an unheated reference channel. ClNO(2) was generated by passing Cl(2) gas over a slurry containing a 1:10 mixture of NaNO(2) and NaCl. The TD-CRDS response was evaluated using parallel measurements of ClNO(2) by chemical ionization mass spectrometry (CIMS) using I(-) as the reagent ion and NO(y) (= NO + NO(2) + HNO(3) + ΣRO(2)NO(2) + ΣRONO(2) + HONO + 2N(2)O(5) + ClNO(2) + ...) chemiluminescence (CL). The linear dynamic range extends from the detection limit of 20 pptv (1 σ, 1 min) to 30 parts-per-billion by volume (ppbv), the highest mixing ratio tested. The ClNO(2) TD profile overlaps with those of alkyl nitrates, which has implications for nocturnal measurements of total alkyl nitrate (ΣAN = ΣRONO(2)) abundances by thermal dissociation (with detection as NO(2)) in ambient air.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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 source (direct Gemma or distilled Codex), 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".