Step-Scan IR Spectroelectrochemistry with Ultramicroelectrodes: Nonsurface Enhanced Detection of Near Femtomole Quantities Using Synchrotron Radiation
Bibliographic record
Abstract
The result of interfacing step-scan spectroelectrochemistry with an IR microscope and synchrotron infrared (SIR) radiation is provided here. An external reflectance cell containing a 25 μm gold ultramicroelectrode is employed to achieve an electrochemical time constant less than one microsecond. The use of a prototypical electrochemical system, i.e., the mass-transport controlled reduction of ferricyanide, allows for a proof of principle evaluation of the viability of SIR for step-scan spectroelectrochemistry. An analysis of the importance of accounting for synchrotron source variation over the prolonged duration of a step-scan experiment is provided. Modeling of the material flux in the restricted diffusion space afforded by the external reflectance cell allows the quantitative IR results to be compared to theoretical predictions. The results indicate that only at very short times does linear diffusion within the cavity dominate the electrode response and the majority of the transient signal operates under conditions of quasi-hemispherical diffusion. The analytical information provided by the IR signal is found to be considerably less than that derived from the current response due the latter's pronounced edge effects. The results provide a detection limit of 36 fmol for step-scan SIR measurements of ferrocyanide. Implications for future IR spectroelectrochemical studies in the microsecond domain are discussed.
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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) | 0.001 | 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 | 0.001 |
| 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 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".