Mass fraction assignment of Amino Acids in acidic aqueous solution (CCQM-K78.a)
Bibliographic record
Abstract
The CCQM-K78.a comparison was coordinated by the BIPM on behalf of the CCQM Organic Analysis Working Group for NMIs and DIs which provide measurement services in organic analysis under the CIPM MRA. The key comparison forms part of the OAWG 10-year strategic plan of comparisons. CCQM-K78.a underpins the demonstration of capabilities for value assignment of high polarity calibration solutions. The model system selected was amino acids in aqueous solution. Participants were required to assign the mass fractions, expressed in μg/g, of phenylalanine (Phe), leucine (Leu), isoleucine (Ile) and proline (Pro) present in solution in 0.01 N hydrochloric acid. The content and analytical challenges of the selected analytes are representative of those for typical calibration solutions for polar organic analytes in aqueous solution. Participation in CCQM-K78, a benchmarked measurement capability for assigning the mass fraction content of polar organic compounds (pK ow > -2) present at a mass fraction range between 50 μg/g and 500 μg/g in an aqueous solution. It also tested capabilities for the quantitative assignment of isomeric polar compounds of similar chromatographic retention time properties. A satisfactory level of agreement of the results was obtained between participants and with gravimetric values for amino acid content. In the cases where the agreement was not satisfactory, the participants were able to identify a technical cause for the inconsistency. The comparison demonstrated the trueness and precision of double IDMS-based methods as a primary measurement procedure for the quantification of polar analytes in aqueous solution when an isotopically labelled version of the analyte is available as the internal standard. It also demonstrated that amino acid quantification using pre- or post-column derivatization with UV or FLD detection can provide results with comparable levels of performance. In this case, where the purity of the primary calibrators had been assigned with a relative standard uncertainty below 0.2%, results consistent with the KCRV within a relative expanded uncertainty in the range 1% - 2% could be realized and levels of 2%-4% were routinely achieved. KEY WORDS FOR SEARCH Amino acid quantification, leucine, isoleucine, proline, phenylalanine, calibration solution, standard solution, IDMS, primary measurement procedure, polar solution, peptide quantification Main text To reach the main text of this paper, click on Final Report . Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/ . The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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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 | 0.008 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 0.008 |
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".