Mercury speciation by capillary gas chromatography with radiofrequency hollow cathode glow discharge atomic emission detection
Bibliographic record
Abstract
Hollow cathode (HC) glow discharge (GD) atomic emission spectrometry (AES) with a radiofrequency (rf) source was investigated as a detector in gas chromatography (GC) for elemental speciation of methylmercury, ethylmercury and inorganic mercury following a Grignard derivatisation reaction (butylmagnesium chloride). The HC design and the transfer line between the source and the GC column are described; in addition, the parameters governing the discharge (pressure, He flow rate, rf power) on the emission of the analytes were optimised. The analytical performance characteristics of this hyphenated technique were evaluated and compared with those of other more common plasmas used as atomic detectors in GC. The absolute detection limits were found to be 0.2, 0.2 and 0.3 pg for methylmercury, ethylmercury and inorganic mercury, respectively, with the variability being lower than 8% RSD at the 10 pg level. Finally, the accuracy of the proposed methodology was successfully tested by analysing two certified reference materials from the National Research Council of Canada (DORM-2 and DOLT-2).
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".