Isotope Labeling Studies on the Electron Impact Mass Spectral Fragmentation Patterns of Chloropropanol Acetates
Bibliographic record
Abstract
Chloropropanol (CP) esters are part of an emerging group of process-induced toxicants that are considered as potential health hazards particularly in palm oil. Mass spectrometry-based methodologies for identification of CP esters in food are critical in overcoming the challenges associated with direct detection methods. In the present study, a convenient strategy was employed to generate all possible CP acetates through reacting acetic anhydride with either glycerol in the presence of a chloride source or the corresponding CPs, such as 3-chloro-, 1,3-dichloro-, 2-chloro-, and 1,2-dichloropropanols, allowing for the identification of the individual CP acetates and assignment of their mass spectral fragmentations. Mass spectral fragmentations were confirmed through the use of the isotopic signature of chlorine in addition to the isotope labeling experiments performed using isotopically labeled precursors, such as [¹³C-U₃] glycerol, [¹³C-U₄] acetic anhydride, [¹³C-2,2'] acetic anhydride, and [d₅] 3-monochloropropane-1,2-diol (3-MCPD) as reactants. Such studies have indicated that all CP esters can undergo two general fragmentations under electron impact (EI) conditions, one generating the acylium ion at m/z 45 and the other generating a chlorinated cyclic acyloxonium ion at m/z 135.6. Considering the fact that such ions can also be generated from any fatty acid containing CP esters after undergoing McLafferty rearrangement, the ion at m/z 135.6 can therefore be considered as a universal marker for the presence of CP esters undergoing EI fragmentation. Furthermore, these studies have also indicated the formation of ions characteristic of CP diesters, monoesters, and dichloro esters.
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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 | 0.000 |
| 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".