Chiral and diastereomeric impurity standards
Enantiomers and diastereomers as traceable standards for chiral HPLC, chiral LC-MS and ICH Q6A/Q11-related impurity control — with stated enantiomeric or diastereomeric excess on the certificate of analysis.
ee / de
stated on COA
Chiral HPLC
separation
SFC
prep option
USP
method alignment
≥98%
ee band typical
Chiral impurities in API specifications
A single chiral center wrong enantiomer is often a specified impurity with a tight limit; multiple centers produce diastereomeric pairs that may need separate qualification.
Reference standards must be configurationally defined — absolute configuration by NMR, chiroptical methods or synthesis from enantiopure starting materials.
Indicative analytical approach
| Scenario | Method | Standard requirement |
|---|---|---|
| Single chiral API | Chiral HPLC (polysaccharide CSP) | Opposite enantiomer at high ee for spike |
| Diastereomeric mixture | Achiral HPLC may resolve | Each diastereomer isolated if unresolved |
| Chiral API + racemization risk | Stability indicating chiral method | Racemate and enriched enantiomer |
| Peptide epimer | Chiral LC-MS or Marfey's | Site-specific D-amino acid building block trace |
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Typical specifications
Enantiomeric excess
≥98%
Opposite enantiomer ≤1–2% typical
Diastereomeric purity
Reported %
When applicable
Identity
NMR + chiral HPLC
Configuration assignment documented
Specific rotation
Optional
Compare to literature where available
Water / solvents
KF / Q3C
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Isolation and synthesis paths
Synthesis from enantiopure pool
Shortest path when commercial (S)- or (R)- building blocks exist; reduces isolation burden.
Chromatographic resolution
SFC or preparative chiral HPLC for mg–g amounts of minor enantiomer from racemic batches.
Configuration proof
Compare retention order to authenticated reference or use independent stereochemical proof.
What you receive
- COA with ee/de and chromatogram
- Structure and stereochemical designation
- Method summary used for enantiomeric purity
- Storage and handling to avoid racemization
- Link to peptide impurity standards when epimer is peptide-related
Frequently asked questions
Yes — that is the usual request for limit testing. We can also supply the pharmacologically active enantiomer for comparison.
Related
Peptide Impurities
Deletion, truncation, oxidation and racemization variants isolated or synthesized to support peptide impurity qualification, method development and regulatory filing narratives under ICH Q3A/Q3B and peptide-specific expectations.
View detailsWorking Standards
Secondary working standards traceable to primary or certified reference materials — qualified under ISO/IEC 17025-style laboratory practice for daily HPLC, GC and titre use without consuming CRM inventory.
View detailsCertified Reference Materials
Impurities and API-related CRMs with certified property values, measurement uncertainty and metrological traceability — produced or distributed under principles aligned with ISO 17034 for method validation and lab accreditation.
View detailsCustom Impurity Synthesis
When catalogue search does not return your peak, we design a synthesis or isolation route for deletion peptides, genotoxic alerts, nitrosamines, metabolites and chiral variants — with a documented package for qualification.
View detailsReady to specify this for your program?
Share sequence, scale and documentation needs. We reply with indicative specs and a project-specific quotation.