Ultra-Performance Liquid Chromatographic Separation and Mass Spectrometric Quantitation of Physiologic Cobalamins
Bibliographic record
Abstract
The current analytical high-performance liquid chromatography (HPLC) methods by which the various forms of cobalamin can be separated and quantified are limited to tedious chromatographic gradients with run times of 20–30 min and limits of detection (LOD) of 2 nM (2.7 ng/mL). This LOD is far above the physiological range of 148–443 pM (200–600 pg/mL) that is the normal total cobalamin level in human plasma. In this manuscript, benefits of ultra-performance liquid chromatography (UPLC) in which the stationary phase particle size may be reduced from 3.5 µm with a mobile-phase backpressure of 6000 psi in traditional analytical HPLC to a stationary phase particle size of 1.7 µm and a mobile phase backpressure of 15,000 psi in UPLC are reported. UPLC can more than double the chromatographic resolution and reduce each chromatographic run time by 10-fold, such that a complete analysis takes only 3 min per sample.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".