<sup>31</sup> P NMR and ESI-MS studies of metal ion-phosphorus pesticide residue complexes
Bibliographic record
Abstract
31 P NMR and ESI-MS structural studies have been carried out for O,O-dimethylphosphorothioate anion (PA – ) interacting with Ag + , Hg 2+ , and Na + cations. Evidence is presented for the formation of PA – ···Ag + and PA – ···Hg 2+ metal complexes and for ionic PA – Na + , with 31 P chemical shift values of 43, 40, and 65 ppm, respectively. The 31 P chemical shifts for PA – ···Ag + and PA – ···Hg 2+ complexes exhibit an initial sharp rise as the [Ag + ]/[PA] and [Hg 2+ ]/[PA] ratio increases from 0 to 1.0 and 0 to 0.5, respectively, and remain almost constant beyond these ratios. These results indicate the formation of 1:1 PA – ···Ag + and 2:1 (PA – ) 2 ···Hg 2+ complexes. Electrospray ionization mass spectroscopy (ESI-MS) revealed peaks corresponding to [O-P(=S)(OCH 3 ) 2 + Ag + H] + and {2[O-P(=S)(OCH 3 ) 2 ] + Hg + H} + for PAH interacting with Ag + and Hg 2+ , supporting the 1:1 PA – ···Ag + and 2:1 (PA – ) 2 ···Hg 2+ stoichiometry. The experimental results support the predominance of species with greater P=O double bond and P–S single bond character, relative to P-O/P=S. Our results on 31 P NMR chemical shifts have a bearing on the use of 31 P chemical shifts as a tool for organophosphorus pesticide identification.
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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 | 0.001 |
| 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".