Detection of mercury and phenylmercury ions using DNA-based fluorescent probe
Bibliographic record
Abstract
A DNA probe labeled with a 4-([4-(dimethylamino)phenyl]azo)benzoic acid (DABCYL) quencher and a carboxyfluorescein (FAM) donor at its 5'- and 3'-termini can be used for the detection of Hg(2+) ions and phenylmercury ions (PhHg(+)). This DNA probe possesses a random coil structure that changes into a hairpin-like structure upon binding Hg(2+) and PhHg(+) ions. As a result, the fluorescence of the FAM unit decreased through quenching between the donor and the quencher. In the presence of ethylenediaminetetraacetic acid (EDTA), the DNA probe allowed the selective detection of PhHg(+) ions at concentrations as low as 70.0 nM, mainly as a result of T-Hg(2+)-T coordination and π-π stacking between the Ph unit and DNA bases. A linear correlation existed between the fluorescence intensity and the concentration of PhHg(+) ions over the range from 0.10 to 1.0 μM (R(2) = 0.99). After acid hydrolysis and neutralization of the samples, all of the mercury species are converted to Hg(2+) ions, allowing us to use the DNA-based probe to determine the concentrations of total mercury species at the nM level. The practicality of this probe has been validated by the analyses of pond water and fish samples, showing its advantages of sensitivity, selectivity, and simplicity.
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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 | 0.000 | 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 | 0.000 |
| 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".