In-line coupling capillary electrochromatography with amperometric detection for analysis of explosive compounds
Bibliographic record
Abstract
Amperometric detection at a bare gold electrode has been in-line coupled with capillary electrochromatography (CEC) for analysis of nitroaromatic and nitroamine explosives in contaminated soils and ground water. The CEC column packed with 3 microm C18 particles performed best using a mobile phase containing 70-80% methanol, 30 or 20% water, 5 mM sodium dodecyl sulfate (SDS) and 10mM 2-(N-morpholino)ethanesulfonic acid (MES). In contrast, the separation column packed with 1.5 km C18 particles exhibited the best separation when only 30% methanol was added to a mobile phase containing 70% water, 7 mM SDS, and 10 mM MES. The detection, based on electrochemical reduction of the explosives (-0.7 or -1 V vs. Ag/AgCl, depending upon the level of methanol in the mobile phase), was compatible with such mobile phases. The detection limits for 13 explosives ranged from 100 to 200 ppb, i.e., about twofold better than those obtained with electrokinetic chromatography (EKC)/amperometric detection. From an operational viewpoint, exhaustive column conditioning was a prerequisite and care should be taken to prevent bubble formation and current breakdown during the course of separation. The CEC column equipped with amperometric detection successfully measured explosives in ground water and extracts prepared from contaminated soils and the results obtained agreed well with those of the U.S. Environmental protection Agency (EPA) method.
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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) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".