A simple colorimetric method for analysis of aqueous phenylenediamines and aniline
Why this work is in the frame
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Bibliographic record
Abstract
A simple and accurate method has been developed for the field and laboratory analysis of four highly toxic substances found in certain industrial wastes in high concentrations. Trinitrobenzenesulfonic acid (TNBS) was used as a colorimetric reagent for 1,4-phenylenediamine (p-PD), 1,2-phenylenediamine (o-PD), 1,3-phenylenediamine (m-PD), and aniline in phosphate buffer of pH 7.4 to form relatively stable compounds that had high absorbance near 430 nm. With sodium sulfite present in the solution at 2 mmol·L–1 or above, higher extinction coefficients were attained and good linear relationships of absorbance with PDs and aniline concentrations were observed. Test times required to achieve maximum absorbance were 60 min for p-PD and m-PD, 30 min for aniline, and 200 min for o-PD. The reliable quantitation ranges were 2–20 µmol·L–1 for p-PD and m-PD and 2–40 µmol·L–1 for o-PD and aniline with the standard error of the estimates being less than 5% in these ranges. Key words: phenylenediamine, aniline, trinitrobenzenesulfonic acid, colorimetric test method.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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 it