Editorial Review
Author: Dr. Elena Vasquez, Ph.D.(Ph.D. Biochemistry · Lead Science Editor)|Reviewed by: Scientific Compliance Reviewer
Last reviewed: April 2026
Interpreting observed vs expected
Peptide mass specifications usually compare a deconvoluted or monoisotopic mass to the theoretical value for the target sequence, within instrument tolerance. Electrospray signals often show multiple charge states (M+nH) that deconvolve to a neutral mass. The COA should state what software and tolerance were used. Glossary: mass spectrometry and molecular weight.
Orthogonal agreement between HPLC purity and mass identity is a typical pair for batch release. For vendor comparison philosophy, read research peptide deals & vendor comparison.
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Frequently Asked Questions
Yes, if the wrong analyte is pure—identity must match the target sequence, not a related species that coelutes. That is why both tests matter.