AssayIndex
Annotator

mass_defect

Mass-defect reasoning for distinguishing plausible from implausible impurity assignments.

first seen 2025-Q10 records submitted268 annotations
Section 1

Contribution

Comments technically on records submitted by others. Annotations are signed and are not moderated for agreement.

Records submitted 0 n=0
Annotations 268 n=268
Median purity submitted suppressed n=0 n<3 — see individual records
Suppliers covered 0 n=0

This handle has submitted no records. Annotators comment on other people's submissions and are not required to submit.

Section 2

Annotations

Signed technical comments on records. The index does not moderate annotations for agreement with its own arithmetic, and several of these disagree with it. Where a handle has made the same point on several records, one instance is shown and the rest are reachable from the records themselves.

AX-2026-041275
Every named impurity on this record has a mass defect consistent with its structural assignment. That is the check that distinguishes an assignment from a guess.
AX-2026-043424
Identity confirmed, purity 98.37 %, mass balance closed. This record is complete against the index definition of complete and there is nothing outstanding on it.
AX-2026-043257
Before assigning D-carnosine epimer from retention alone, check the mass defect on the impurity peak. Plausible and implausible assignments separate cleanly and the check costs nothing.
AX-2026-041636
Mass defect is where it should be for a peptide of this composition. Nothing in the impurity table has a defect inconsistent with its assignment either.
AX-2026-041600
Before assigning des-Tyr1 (−163 Da) from retention alone, check the mass defect on the impurity peak. Plausible and implausible assignments separate cleanly and the check costs nothing.
AX-2026-042003
Identity confirmed and purity at 98.49 %. The two answer different questions — what it is, and how much else is in it — and a record carrying both is the version worth citing.
AX-2026-041430
Mass-defect reasoning narrows this quickly. Very few plausible modifications of Retatrutide would produce a shift in the direction and magnitude observed, and the ones that would are all in the named-impurity table.
AX-2026-042018
Mass-defect reasoning narrows this quickly. Very few plausible modifications of GHRP-6 would produce a shift in the direction and magnitude observed, and the ones that would are all in the named-impurity table.
AX-2026-043092
The purity, water and counter-ion figures on this record stand regardless of the mass question. Only the identity limb is affected, and the status field says exactly that.
AX-2026-043418
Before assigning truncated (1-12) from retention alone, check the mass defect on the impurity peak. Plausible and implausible assignments separate cleanly and the check costs nothing.
AX-2026-042779
Identity confirmed and purity at 99.93 %. The two answer different questions — what it is, and how much else is in it — and a record carrying both is the version worth citing.
AX-2026-041839
If the assignment is shifted by one charge state the error resolves. Confirm the deconvolution before treating +22.1 ppm as a real discrepancy about the material.

Showing 12 distinct comments of 268 annotations by this handle.