Determination and characterization of naphthenic acids from the oil sands mine tailings in Alberta
Bibliographic record
Abstract
Naphthenic acids (NAs) are complex mixtures of naturally occurring acyclic and cyclic aliphatic carboxylic acids, with general formula CnH 2'n+Z'O2. They are responsible for the toxicity of the water in the tailings ponds of the oil sands mining industry. In this work, negative ion electrospray ionization mass spectrometry (ESI-MS) has been proved to be a reliable and sensitive method for the characterization of NAs. ESI-MS was shown to be superior to atmospheric pressure chemical ionization mass spectrometry (APCI-MS) for the quantification of congeners using a standard addition procedure. Direct analysis of NAs from the tailings pond water was unsuccessful due to background ions' interference. Partial separation of the congeners was achieved with anion exchange chromatography, and the fractions were subjected to ESI-MS analysis and toxicity assessment using the Microtox assay. This suggested that the Z = -4 family was responsible for a significant part of the aquatic toxicity of NAs.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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 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".