Direct, Selective, and Rapid Measurement of HCN at Sub-ppb Levels Using HiT-CD-IMS: Applications to Cell Culture and Breath Analysis
Bibliographic record
Abstract
This study demonstrates the use of a research-grade ion mobility spectrometer combined with a high-temperature negative corona discharge ionization source (HiT-CD-IMS) to detect hydrogen cyanide (HCN) emitted by Pseudomonas aeruginosa (PA) cultures and in human breath. The HCN spectrum revealed distinct peaks for CN –, CNO –, and (CN) 2 – ions, with a resolving power of 63, successfully overcoming potential interferences such as the H 2 S peak by optimizing the experimental conditions. This approach achieved an estimated limit of detection (LOD) of 0.18 ppb. The method was applied to monitor HCN production in PA cultures, demonstrating a clear correlation between bacterial growth and HCN emission. Additionally, breath samples from the mouth cavity and nose-exhaled samples showed measurable HCN concentrations in the range of 40–300 ppb and below 10 ppb, respectively. The technique’s ability to measure HCN in complex biological environments with high sensitivity, even in the presence of water vapor and common respiratory compounds, underscores its potential for noninvasive detection of Pseudomonas aeruginosa in infections.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".