Understanding Peptide Purity: HPLC vs Mass Spectrometry

A purity figure such as 98% means that 98% or more of the detected material is the target peptide, with the remainder comprising related impurities — truncated sequences, deletion peptides, oxidised variants, or residual synthesis reagents.

For reproducible in-vitro research, high purity is essential. Impurities can produce off-target effects in cell assays, confounding results and making data difficult to interpret or replicate.

HPLC separates a compound mixture based on the differential interaction of components with a stationary phase and a mobile phase. Purity by HPLC is calculated as the percentage area of the target peptide peak relative to the total peak area. A result of 98% by HPLC means the target peptide accounts for at least 98% of the total detected material.

HPLC is the primary purity verification method for research peptides and should be present on every lot-specific CoA from a credible supplier.

Mass spectrometry measures the mass-to-charge ratio of ionised molecules, confirming molecular identity. For peptides, it confirms the compound has the correct molecular weight — verifying it is the intended peptide rather than a structural analogue.

Mass spectrometry confirms identity. Used together, HPLC and mass spectrometry provide both purity and identity verification — the two pillars of research-grade quality assurance.

A credible lot-specific CoA should include:

• Product name and CAS number
• Lot or batch number
• HPLC purity result as a percentage
• Mass spectrometry result confirming molecular weight
• Appearance description
• Storage conditions

All compounds supplied by Alluvi Labs are verified to 98% purity by HPLC with mass spectrometry identity confirmation. Batch-specific certificates of analysis are available for every lot. Compounds are dispatched cold within 48 hours.