Low-level 40Ca determinations using nitrous oxide with reaction cell inductively coupled plasma–tandem mass spectrometry
Bibliographic record
Abstract
Abstract In inductively coupled plasma mass spectrometry, the most abundant Ca isotope ( 40 Ca) suffers from isobaric interference with argon, hindering the potential for low detection limits of Ca. A powerful approach is to remove the interference by using a reaction gas in a reaction cell. Ammonia (NH 3 ) has proven to be an effective reaction gas by process of a charge transfer reaction. However, NH 3 is highly corrosive and toxic and cannot remove isobaric 40 K. Therefore, this work proposes the use of nitrous oxide (N 2 O) to mass shift the target analyte 40 Ca to 40 Ca 16 O + as a non-corrosive and non-toxic alternative. Instrument performance testing demonstrated that N 2 O was capable of reaching equivalent detection limits (0.015 ng g −1 ) and background equivalence concentrations (0.041 ng g −1 ) to that of NH 3 and limited by the blank only. Further investigation of matrix interferences with synthetic standards highlighted that the N 2 O approach supports the separation of potassium (K) and magnesium (Mg)–based interferences at tested concentrations of more than 600 times and almost 800 times higher than Ca respectively, whereas NH 3 was found to only support the removal of Mg. This work highlights a clear advantage of N 2 O for low-level Ca determinations with high matrix loads, as well as compatibility with other instrumentation sensitive to corrosion that supports reaction cell technology. Graphical abstract
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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".