N,N-Diethyl-p-phenylenediamine effectiveness in analysis of polysulfides and polythionates in water
Bibliographic record
Abstract
Environmental context. The importance of hydrogen sulfide as well as some of the reduced sulfur species such as polysulfides as environmental pollutants is a result of their toxicity, unpleasant odour, and their reactivity with metals and metallic ions found in various environmental samples. Although known to be popular, the effectiveness of N,N-diethyl-p-phenylenediamine and other related compounds in the spectrophotometric analysis of such sulfur compounds in water as well as in other environmental samples has not been fully investigated. Our results show that although the quantification of simple sulfides in the environmental samples may be easily accomplished spectrophotometrically by using N,N-diethyl-p-phenylenediamine, the level of difficulty in analysing such compounds may increase with their increasing sulfur chain. Abstract. The analysis of polysulfides, polythionates and other sulfur species likely to be found in poorly aerated environmental samples such as water is presented. In-depth spectrophotometric testing carried out using N,N-diethyl-p-phenylenediamine shows that the well known acidification-and-purge method is not sufficiently suitable for the analysis of polysulfides and other low oxidation-state sulfur compounds that contain a sulfur chain longer than two. Further, this study finds that the use of chromium(II) which acts as a reducing agent to the sulfur-containing compounds improves the spectrophotometric analysis of the polysulfides and polythionates in water, but only slightly. The extent of reduction of polysulfides and polythionates to sulfide by chromium appears dependent upon the oxidation state of sulfur as well as the chain length in the polysulfidic compounds.
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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 | 0.000 |
| 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 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".