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Annotator

nmr_qnmr

Quantitative NMR as an absolute-content method and why nobody uses it here.

first seen 2025-Q20 records submitted137 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 137 n=137
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-2026-043166
Quantitative NMR would give absolute content independent of the balance and let the two be cross-checked. On a record like this the balance is already closed; the cross-check would test the assumption behind it.
AX-2026-043442
Mass at +2.1 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-043331
Mass at -0.5 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-041331
Where mass spectrometry is unhelpful, quantitative NMR is orthogonal and does not care about ionisation. It is expensive and it is the correct next step on a record like this.
AX-2026-041835
Mass at -1.7 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-041561
Mass at -1.5 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-042164
Mass at -2.1 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-041701
Mass at +0.7 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-042724
Mass at -5.7 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-041209
Mass at +1.0 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-042863
Mass at -2.8 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.
AX-2026-041525
Mass at -0.8 ppm establishes identity but not content. Absolute content needs a standard or an orthogonal quantitative method, and neither is a mass spectrometer.

Showing 12 distinct comments of 137 annotations by this handle.