Analytical quality
Why retention time alone does not prove identity
Retention time and identity: Was matching retention observed under the same conditions?
Source editorial review:
Before interpreting the result
Was matching retention observed under the same conditions?
- Keep the column, mobile phase, gradient, flow and relevant method conditions.
- Distinguish a reference run with the sample from a time quoted from another publication.
- Look for independent evidence resolving coelution or signal identity.
Retention time and identity
Retention time belongs to a particular separation. Column, mobile-phase composition, gradient and other conditions affect when a signal appears. Matching minutes does not make two samples the same substance, and a method change can shift a signal without changing identity. Comparison becomes more informative with an appropriate reference and additional evidence independent of retention.
A reading case: what to check
When receiving two chromatograms, compare methods before peaks. If conditions differ, do not treat a timing difference as evidence of degradation. Even with matching conditions, several components may occupy the same elution region. Document the evidence used to assign a peak; a label drawn above it does not replace that justification.
What to preserve in the record
Matching minutes is a property of the separation system. Do not use it as universal identification or turn a retention difference between methods into proof of a different compound.
Questions and answers
Was matching retention observed under the same conditions?
Retention time belongs to a particular separation. Column, mobile-phase composition, gradient and other conditions affect when a signal appears. Matching minutes does not make two samples the same substance, and a method change can shift a signal without changing identity. Comparison becomes more informative with an appropriate reference and additional evidence independent of retention.
What should the review record preserve?
Matching minutes is a property of the separation system. Do not use it as universal identification or turn a retention difference between methods into proof of a different compound.
Sources
- Generation of accurate peptide retention data for targeted and data independent quantitative LC-MS analysis: Chromatographic lessons in proteomics.
- CharmeRT: Boosting Peptide Identifications by Chimeric Spectra Identification and Retention Time Prediction.
- ICH Q6A: especificaciones y pruebas de identificación