Factors influencing enantiomeric fractions of hexabromocyclododecane measured using liquid chromatography/tandem mass spectrometry
Bibliographic record
Abstract
Hexabromocyclododecane (HBCD), the most heavily produced of the cycloaliphatic brominated flame retardants (BFRs), is a mixture of three predominant diastereomers (alpha-, beta-, and gamma-HBCD), each with a corresponding pair of enantiomers. We have investigated the liquid chromatography/mass spectrometry (LC/MS) behaviour of the HBCD enantiomers, and demonstrated that enantiomeric fractions (EFs) calculated using data uncorrected for instrument and/or matrix effects can result in potentially inaccurate EF values. However, use of labelled surrogates effectively corrects for these effects. Experiments with racemic HBCD standards indicate that chromatographic factors, including mobile phase composition and column bleed from chiral stationary phases, may be contributors to variations in the mass spectrometric response of the HBCD enantiomers.
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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 | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.008 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".