Topic · Analytics
“A new peak above the identification threshold, and no structure yet.”
NMR analysis and structure elucidation
When ICH Q3A(R2) requires a structure, why NMR or a reference standard decides in the end, and how CovaSyn shortens the way there: predict spectra for a structure, narrow hypotheses from MS data, name the deciding experiment.
Regulation
Obligations and deadlines
What the guidelines set out for identification, as stated in our Insights articles. Check the thresholds against your actual daily dose.
| Framework | What applies | Threshold or deadline |
|---|---|---|
| ICH Q3A(R2), reporting threshold | New drug substance with a maximum daily dose up to 2 g per day. Below the reporting threshold nothing is reported. | 0.05 % |
| ICH Q3A(R2), identification threshold | Above the identification threshold you owe a structure. “Unknown at RRT 1.12” is not an acceptable end state. | 0.10 % or 1.0 mg daily intake, whichever is lower (daily dose up to 2 g) |
| Regulatory identification | An authentic reference standard or isolated material with orthogonal structural data. In-silico annotation narrows hypotheses; it does not identify. | |
| ICH Q1A(R2), forced degradation | The results of stress testing should identify likely degradation products. |
Sources: our articles on unknown impurity identification and on forced degradation study design, linked below. There is no dedicated article on NMR analysis yet.
CovaSyn
How CovaSyn does it
CovaSyn computes deterministically: same structure, same result. The prediction tells you which experiment decides; the confirmation comes from your lab.
Predict spectra for a structure
Predict NMR, MS and IR for the structure you drew, in the sketcher with an account or directly in your AI assistant.
Does the spectrum fit the structure?
Assess identity, purity and impurities from NMR, MS, IR and UV/Vis, with the same computation on every call.
Narrow hypotheses from MS data
Formula from accurate mass, ring and double bond equivalents, isotope pattern and MS/MS logic give a ranked list of candidates and the experiment that decides between them.
Every step logged
Timestamp, tool and version per call, outputs with a SHA-256 checksum. How a structure hypothesis came about stays traceable.
What the computation does not replace
- A prediction identifies nothing. It gives a ranked hypothesis; confirmation needs a reference standard or NMR on isolated material.
- Positional isomers cannot be told apart from mass and fragments alone. Chromatography against standards or NMR settles that.
- A matching retention time is consistent with an assignment but never establishes it.
Insights
Read on and try it yourself
Unknown Impurity Identification by LC-MS/MS
Unknown impurity identification by LC-MS: formula from accurate mass, RDBE, isotope pattern and MS/MS fragment logic, with real CovaMS tool output and its.
Read articleForced Degradation Study Design (ICH Q1A R2)
Forced degradation study design under ICH Q1A(R2): stressor choice, target degradation, mass balance and stability-indicating methods, with real tool output.
Read articleMass Balance in Forced Degradation, and Why It Fails
Why mass balance in forced degradation rarely closes: non-chromophoric and volatile degradants, adsorption and response factors, plus how to close the gap.
Read articleRetention Time Prediction in HPLC Method Development
What retention time prediction in HPLC is actually good for, what it is not, and a worked impurity panel with real chromaopt_predict_rt outputs.
Read article
Questions
Common questions
Does in-silico annotation replace a reference standard?
No. It narrows the hypothesis space and tells you which experiment decides. It does not confirm positional isomers or stereochemistry; regulatory identification needs an authentic standard or isolated material with orthogonal structural data.
Next step
Predict the spectra of your structure.
Create an account, get your API key, use the tools in Claude, ChatGPT or Cursor.