Quantitative Analysis of Volatile Methylsiloxanes in Waste-to-Energy Landfill Biogases Using Direct APCI-MS/MS
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Landfill-biogas utilization is a win-win solution as it creates sources of renewable energy and revenue while diminishing greenhouse gas emissions. However, the combustion of a siloxane-containing biogas produces abrasive microcrystalline silica that causes severe and expensive damages to power generation equipment. Hence, the importance of siloxane analysis of the biogas has increased with the growth of the waste-to-energy market. We have investigated an improved method for the analysis of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in biogas using deuterated hexamethyldisiloxane (HMDS-d(18)) as an internal standard with direct atmospheric pressure chemical ionization/tandem mass spectrometry (APCI-MS/MS). The use of HMDS-d(18) as a single internal standard provided effective signal compensation for both D4 and D5 in biogas and improved the sensitivity and reliability for the direct APCI-MS/MS quantification of these compounds in biogas. Low detection limits ( approximately 2 microg/m(3)) were achieved. The method was successfully applied for the determination of D4 and D5 contents in various samples of biogas recovered for electrical power generation from a landfill site in Montreal. Concentrations measured for D4 and D5 were in the ranges of 131-1275 and 250-6226 microg/m(3), respectively. Among the various landfill zones sampled, a clear trend of decreasing D4 and D5 concentrations was observed for older landfill materials.
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.
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 | 0.002 | 0.004 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 it