A Continuous Visible Light Spectrophotometric Approach To Accurately Determine the Reactivity of Radical-Trapping Antioxidants
Bibliographic record
Abstract
Inhibited autoxidations-monitored either by O2 consumption or hydroperoxide formation-are the most reliable way to obtain kinetic and stoichiometric information on the activity of radical-trapping antioxidants (RTAs). While many comparatively simple "antioxidant assays" (e.g., the DPPH assay) have supplanted these in popularity, they are generally very poor substitutes since they often do not employ peroxyl radicals as the oxidant and do not account for both the kinetics and stoichiometry of the radical-trapping reaction(s). In an effort to make inhibited autoxidations as simple as the most popular "antioxidant assays", we have developed a spectrophotometric approach for monitoring reaction progress in inhibited autoxidations. The approach employs easily prepared 1-phenylbutadiene-conjugated or styrene-conjugated BODIPY chromophores (PBD-BODIPY or STY-BODIPY, respectively) as signal carriers that co-autoxidize along with a hydrocarbon substrate. We show that inhibition rate constants (kinh) are accurately determined for a range of phenolic and diarylamine RTAs using this approach and that mechanistic experiments, such as kinetic isotope effects and kinetic solvent effects, are equally easily carried out. Moreover, synergistic interactions between RTAs, as well as the unconventional activity of diarylamine RTAs, are captured using this methodology. Lastly, we show that the approach can be employed for monitoring reactions in aqueous solution.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.003 |
| Insufficient payload (model declined to judge) | 0.001 | 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; 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".