Alternative Sample Introduction Techniques to Nebulization of Solutions in Inductively Coupled Plasma Spectrometry
Bibliographic record
Abstract
The objective of this thesis was to explore alternative sample introduction techniques for inductively coupled plasma mass spectrometry (ICPMS) and optical emission spectrometry (ICPOES). This work was conducted as part of a Collaborative Research and Development project with Activation Laboratories Ltd., Ancaster, Ontario. 1. The first approach involved the development of a sample preparation method for the direct analysis of lithium borate fused X-ray fluorescence (XRF) discs by ICPMS with a mixed-gas plasma and flow injection for the introduction of slurries into the ICP. Three dispersing agents were initially explored, however a 4% (m/m) solution of Triton-X in 2% HNO3 DDW was found to homogenously suspend the ground particulate in solution, yielding highly reproducible injection peaks. External calibration by aqueous standards did not yield consistent results to the certified values at high slurry concentrations, regardless if matrix matching of the standard was performed. Calibration by standard addition was also explored and was found to be most accurate when the slurry concentration was well diluted and that the flow rate of the carrier did not exceed 1 mL/min, as it was suspected that particle agglomeration was occurring at higher slurry concentration and higher flow rates. 2. The second approach involved electrothermal vaporization (ETV) coupled to ICPOES for the analysis of solid fire assay buttons. A nebulization/pre-evaporation system was initially explored to prevent plasma overloading due to the mass of the button, however a N2 sheath gas was selected as it provided higher plasma robustness conditions to that of the previous approach. External calibration by aqueous standards were improved upon through utilization of the internal ETV temperature program and a venting valve system for the drying of solution. Significant Ag2S deposition along the inner transfer tube prevented accurate agreement of calculated to certified values by both aqueous and solid external calibration due to the differences in transport efficiencies. The addition of an optimized H2 gas flow rate into the reaction gas aided in reducing Ag2S deposition along the transfer tube to the plasma, however non-proportional signal to mass intensities were still observed as Ag2S deposition was not eliminated.
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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 | 0.003 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.003 | 0.003 |
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".