H <sub>2</sub> S interference on CO <sub>2</sub> isotopic measurements using a Picarro G1101-i cavity ring-down spectrometer
Bibliographic record
Abstract
Abstract. Cavity ring-down spectrometers (CRDSs) have the capacity to make isotopic measurements of CO2 where concentrations range from atmospheric (~ 400 ppm) to 6000 ppm. Following field trials, it has come to light that the spectrographic lines used for CO2 have an interference with elevated (higher than ambient) amounts of hydrogen sulfide (H2S), which causes significant depletions in the δ13C measurement by the CRDSs. In order to deploy this instrument in environments with elevated H2S concentrations (i.e., active volcanoes), we require a robust method for eliminating this interference. Controlled experiments using a Picarro G1101-i optical spectrometer were done to characterize the H2S interference at varying CO2 and H2S concentrations. The addition of H2S to a CO2 standard gas reveals an increase in the 12CO2 concentration and a more significant decrease in the 13CO2 concentration, resulting in a depleted δ13C value. Reacting gas samples containing H2S with copper prior to analysis can eliminate this effect. Models post-dating the G1101-i carbon isotope analyzer have maintained the same spectral lines for CO2 and are likely to have a similar H2S response at elevated H2S concentrations. It is important for future work with CRDS, particularly in volcanic regions where H2S is abundant, to be aware of the H2S interference on the CO2 spectroscopic lines and to remove all H2S prior to analysis. We suggest employing a scrub composed of copper to remove H2S from all gas samples that have concentrations in excess of 1 ppb.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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".