Application of 10 <sup>13</sup> ohm Faraday cup current amplifiers for boron isotopic analyses by solution mode and laser ablation multicollector inductively coupled plasma mass spectrometry
Bibliographic record
Abstract
Rationale Boron isotope ratios (δ 11 B values) are used as a proxy for seawater paleo‐pH, amongst several other applications. The analytical precision can be limited by the detection of low intensity ion beams from limited sample amounts. High‐gain amplifiers offer improvements in signal/noise ratio and can be used to increase measurement precision and reduce sample amounts. Methods 10 13 ohm amplifier technology has previously been applied to several radiogenic systems, but has thus far not been applied to non‐traditional stable isotopes. Here we apply 10 13 ohm amplifier technology for the measurement of boron isotope ratios using solution mode MC‐ICP‐MS and laser ablation mode (LA‐)MC‐ICP‐MS techniques. Precision is shown for reference materials as well as for low‐volume foraminifera samples. Results The baseline uncertainty for a 0.1 pA 10 B + ion beam is reduced to <0.1 ‰ for a typical measurement period. The external precision is better than 0.2 ‰ (2SD) for δ 11 B measurements for solution samples containing as little as 0.8 ng total boron. For in situ microanalyses with LA‐MC‐ICP‐MS, the external precision of 11 B/ 10 B from an in‐house calcite standard was 1 ‰ (2SD) for individual spot analyses, and 0.3 ‰ for the mean of ≥10 replicate spot analyses. Conclusions 10 13 ohm amplifier technology is demonstrated to offer advantages for the determination of δ 11 B values by both MC‐ICP‐MS and LA‐MC‐ICP‐MS for small samples of biogenic carbonates, such as foraminifera shells. 10 13 ohm amplifier technology will also be of benefit to other non‐traditional stable isotope measurements.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".