Multi-reflecting TOF MS for analyzing proteins
Bibliographic record
Abstract
This paper presents detailed results of previously reported protein studies conducted using a prototype multi-reflecting time-of-flight mass spectrometer with orthogonal acceleration (o-MRT). The o-MRT instrument features a relatively short 5-m effective flight path to minimize gas scattering of protein ions. Despite this, the instrument achieves an impressive mass resolving power exceeding 200,000, fully resolving isotopic envelopes for proteins up to 80 kDa. For multiply charged ions of mid-sized proteins (up to 30 kDa), the instrument's resolution surpasses 250,000, enabling efficient charge and isotope deconvolution. This process consolidates multiple peaks from a specific proteoform into a single molecular weight peak, significantly simplifying protein spectra and facilitating accurate mass measurements. Mass analysis of horse myoglobin demonstrates exceptional mass precision, achieving 100 ppb accuracy for the monoisotopic mass. The o-MRT instrument exhibits a sensitivity of 10 4 ions/fmol, allowing for the detection of horse myoglobin from 100 pM to 10 μM concentration range. It accurately identifies known proteoforms in exemplar mixtures of seven proteins without chromatography, demonstrating a dynamic range of 1000. The o-MRT instrument showcases versatility in MS/MS analysis, achieving over 80 % sequence coverage for proteoforms. In MS/MS analyses of horse myoglobin and human hemoglobin chain A, mass accuracy of 0.5 ppm is maintained over a dynamic range of 1000. With future coupling to liquid chromatography, the compact o-MRT instrument is expected to be a valuable tool for identifying proteins within moderately complex mixtures. • A compact o-MRT instrument provides 10 5 dynamic range and resolution of R=250,000. • Isotopic envelopes are resolved for proteins with mass up to 80 kDa. • Monoisotopic mass of mid size proteins is measured with 100 ppb accuracy. • Deconvolving isotopic patterns and charge states forms single MW peak per protein. • MS/MS spectra provide over 80% sequence coverage.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".