Detection, Identification, and Quantification of Hydroxylated\nBis(2-ethylhexyl)-Tetrabromophthalate Isomers in House Dust
Bibliographic record
Abstract
Ultra-High Resolution LC/mass spectrometry\n(LC-UHRMS; Thermo Fisher Q-Exactive) was used to identify two novel\nisomers of hydroxylated bis(2-ethylhexyl)-tetrabromophthalate (OH-TBPH)\nwhich were unexpectedly observed in a commercial standard of TBPH.\nBy combining ultra-high resolution (UHR) mass spectra (MS<sup>1</sup>), mass errors to\ntheoretical [TBPH-Br+O]<sup>−</sup> were 2.1 and 1.0 ppm for\nthe two isomers, UHR-MS<sup>2</sup> spectra and NMR analysis; the\nstructures of the two compounds were identified as hydroxylated TBPH\nwith a hydroxyl group on the aromatic ring. Relatively great proportions\nof the two isomers of OH-TBPH were detected in two technical products,\nFiremaster 550 (FM-550; 0.1% and 6.2%, respectively) and Firemaster\nBZ 54 (BZ-54; 0.1% and 7.9%), compared to a commercial standard (0.4%\nand 0.9%). To simultaneously analyze OH-TBPH isomers and TBPH in samples\nof dust, a method based on LC-UHRMS was developed to quantify the\ntwo compounds, using negative and positive ion modes, respectively.\nThe instrumental limit of detection for TBPH was 0.01 μg/L,\nwhich was 200–300 times better than traditional methods (2.5\nμg/L) based on gas chromatography–mass spectrometry.\nThe analytical method combined with a Florisil cleanup was successfully\napplied to analyze TBPH and OH-TBPH in 23 indoor dust samples from\nSaskatoon, Saskatchewan, Canada. Two OH-TBPH isomers, OH-TBPH1 and\nOH-TBPH2, were detected in 52% and 91% of dust samples, respectively.\nConcentrations of OH-TBPH2 (0.35 ± 1.0 ng/g) were 10-fold greater\nthan those of OH-TBPH1 (0.04 ± 0.88 ng/g) in dust, which was\nsimilar to profiles in FM-550 and BZ-54. TBPH was also detected in\n100% of dust samples with a mean concentration of 733 ± 0.87\nng/g. A significant (<i>p</i> < 0.001) log–linear\nrelationship was observed between TBPH and OH-TBPH isomers, further\nsupporting the hypothesis of a common source of emission. Relatively\nsmall proportions of OH-TBPH isomers were detected in dust (0.01%\n± 0.67 OH-TBPH1 and 0.1% ± 0.60 OH-TBPH2), which were significantly\nless than those in technical products (<i>p</i> < 0.001).\nThis result indicated different environmental behaviors of OH-TBPH\nand TBPH. Detection of isomers of OH-TBPH is important, since compounds\nwith phenolic groups have often shown relatively greater toxicities\nthan nonhydroxylated analogues. Further study is warranted to clarify\nthe environmental behaviors and potential toxicities of OH-TBPH isomers.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.051 | 0.001 |
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; both teacher heads agree on what is shown here.
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".