Modification of Glassy Carbon Electrode by Electrografting of In Situ Generated 3-diazopyridinium Cations
Bibliographic record
Abstract
The effect of various parameters on the grafting of pyridine, by electrochemical reduction of 3-diazopyridinium cations generated in-situ, on a glassy carbon electrode was investigated. More specifically, the influence of 3-aminopyridine and NaNO 2 concentration used for the diazotization reaction and the influence of the grafting conditions such as time and potential used for reduction of the diazonium cations, were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The presence of immobilized pyridine at the electrode surface was demonstrated by X-ray photoelectron spectroscopy measurements and indirectly, by the blocking effect of the grafted layer. The best blocking effect is obtained for a diazotization reaction of 1 min. and 1 equivalent of sodium nitrite. As a general observation, when the time is increased and the reduction potential is made more negative, the higher blocking effect that is observed indicates a more compact layer and a higher surface coverage of the glassy carbon electrode. The apparent pKa of the immobilized pyridine was determined by cyclic voltammetry in the presence of Fe(CN) 6 3−/4− solution of different pHs and found to be equal to 5, which is close to the pK a value (5.25) of pyridine in homogeneous 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 | 0.000 | 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) | 0.001 | 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 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".