Capillary electrophoresis‐electrospray‐mass spectrometry of nucleosides and nucleotides: Application to phosphorylation studies of anti‐human immunodeficiency virus nucleosides in a human hepatoma cell line
Bibliographic record
Abstract
We report the use of capillary electrophoresis-electrospray ionization-mass spectrometry (CE-ESI-MS) for the determination of antiretroviral dideoxynucleosides (ddNs), their nucleotides, and a set of ribonucleosides and ribonucleotides. A CE system for separation of most commonly used antiretroviral ddNs has been developed based on a basic buffer with a volatile electrolyte suitable for ESI-MS detection in an untreated capillary column. Positive and negative ionization modes are investigated and compared for sensitive and stable electrospray performance. A 14-compound mixture of nucleosides and nucleotides is profiled in a single capillary zone electrophoresis separation with a distinct elution order: electroosmotic flow, ddNs, mononucleotides, dinucleotides, and trinucleotides in less than 18 min. The fragmentation pathways of the nucleosides and nucleotides in ESI-MS have been interpreted. Concentration limits of detection are 100 to 200 nM with an injection volume of approximately 10 nL. This technique has been used to detect naturally occurring nucleotides and to study the metabolism of lamivudine (3TC) in the human hepatoma cell line Hep G2. 3TC and its metabolites 3TC-monophosphate, 3TC-diphosphate, and 3TC-triphosphate were detected after 10 h of incubation of 3TC with the cells.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".