Internal standard signal suppression by co-eluting analyte in isotope dilution LC-ESI-MS
Why this work is in the frame
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Bibliographic record
Abstract
The suppression of the internal standard by increasing concentrations of the co-eluting analyte in calibration series and plasma samples analysed by LC-ESI-MS was studied using the isotope dilution technique. A series of three analyte/deuterated analyte pairs including fexofenadine/d6-fexofenadine, dapsone/d4-dapsone and peudoephedrine/d3-ephedrine were investigated. Suppression of the internal standard signal was noticed in extracted plasma samples containing fexofenadine and d6-fexofenadine as internal standard, as well as in solvent based calibration solutions of the three pair of compounds noted above during LC-ESI-MS analysis at flow rates greater than 100 microL min(-1). This signal suppression effect was described by invoking Enke's model of electrospray ion generation. This model suggests that signal suppression can be ascribed to the competition between ionic species for charged surface sites present on the generated droplets during the electrospray process. The slopes of the calibration curves of the three analytes were close to unity (fexofenadien/d6-fexofenadine 0.964 +/- 0.008, pseudoephedrine/d3-ephedrine 1.02 +/- 0.080 and dapsone/d4-dapsone 0.905 +/- 0.048) as predicted by the model, indicating that quantitation should not be affected by the variation in the peak area of the internal standard.
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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) | 0.016 | 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 it