Stopped-flow electrospray ionization mass spectrometry: a new method for studying chemical reaction kinetics in solution
Bibliographic record
Abstract
In this work a new mass spectrometry based method for monitoring the kinetics of chemical reactions in solution is described. A stopped-flow mixing instrument is coupled to an electrospray ionization (ESI) mass spectrometer via a novel type of interface. Chemical reactions are initiated by rapid mixing of two reactant solutions. The mixture is instantaneously transferred to a reaction tube where the kinetics can be monitored in real-time by ESI mass spectrometry. With the current setup, a time window from 2.5 to 36 seconds after mixing of the reactants can be monitored. The experimental setup is used to study the kinetics of acetylcholine hydrolysis under alkaline conditions as a function of pH. The intensities of reactant (acetylcholine) and product (choline) ions are monitored simultaneously as a function of time. The reaction is carried out under pseudo-first-order conditions and the intensity-time curves are well described by single exponentials. The rate constants determined from these fits compare favorably with previous data from the literature.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".