Determination of chromium picolinate and trace hexavalent chromium in multivitamins and supplements by HPLC-ICP-QQQ-MS
Bibliographic record
Abstract
Chromium picolinate (CrPic) and trace hexavalent chromium (Cr(VI)) content were characterized in VITA-1 and VITB-1, two new multivitamin and mineral supplement candidate reference materials from National Research Council Canada, by two methods of high performance liquid chromatography inductively-coupled plasma triple quadrupole mass spectrometry. The conditions for the separation of Cr(VI) from EDTA-complexed Cr(III) were optimized such that species interconversions were not observed during analysis. Following extraction with dilute NH4OH in water at pH 10 (for Cr(VI)) or 3:2 acetonitrile:water (for CrPic) and quantification by standard addition, it was concluded that CrPic accounted for 95-96% of the Cr in VITA-1 and VITB-1, while Cr(VI) was not present above the detection limit of 0.13 µg Cr g-1. Using the two developed methodologies, commercially-available nutritional supplements, in the form of vitamin tablets and dried food supplements, were assessed, and it was determined that CrPic accounted for the majority (92%-98%) of the chromium present in the tablets, and that Cr(VI) concentrations were below the detection limit for all samples except for the powdered beets where it accounted for nearly half of the total Cr present.
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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 | 0.000 | 0.001 |
| 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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".